Homocystinuria H. H. WHITE, MD, KANSAS CITY, KAN; L. P. ROWLAND, MD; S. ARAKI, MD, NEW YORK; H. L. THOMPSON, PhD, EL PASO, TEXAS; AND D. COWEN, MD, NEW YORK IN NOVEMBER, 1962, a family with an unusual neurological disorder was encountered. When the urinary excretion of amino acids was studied in January 1963, a unique pattern was seen and we thought we were dealing with a new syndrome. It soon became apparent that the same disorder had been described by Carson and Neill,5 and Gerritsen et al11 during the preceding months. These authors, together with Cusworth, Dent, Field and Westall 3,7 had identified the abnormal compound as homocystine. Since then about 20 cases have been discovered 1,3,7,12,16,18,23 and the biochemical abnormality has been identified as a deficiency of cystathionine synthetase.23 The family to be described here illustrates the typical features of the disease. Biochemical and neuropathological studies were carried out in two of three affected individuals (cases 2 and 3), and some neuropathological data were available in the third (case 1). Report of Cases Family Background.\p=m-\Theparents, of Dutch descent, are healthy and asymptomatic. There is no evidence of consanguinity. The mother had four pregnancies : three children were affected, and the second pregnancy ended in spontaneous abortion at six months. The father had one female Submitted for publication May 25, 1965; accepted July 6. Read in part before the 89th Annual Meeting of the Ameri- Neurological Association, June 1964. From the Neurology Service, William Beaumont General Hospital, El Paso, Tex; the departments of neurology and pathology (division of neuropathology) Columbia University; and the Neurological Clinical Research Center, Neurological Institute, Columbia-Presbyterian Medical Center, New York. Formerly Captain (MC) US Army, presently assistant professor of Medicine (neurology) University of Kansas (Dr. White); associate professor of neurology, Columbia University, (Dr. Rowland); formerly Fellow, National Multiple Sclerosis Society at Columbia University, presently associate professor of neurology, Kyushu University, Japan (Dr. Araki); Lt Col US Army (Dr. Thompson); professor of neuropathology, Columbia University (Dr. Cowen). Reprint requests to 710 W 168th St, New York, NY 10032 (Dr. Rowland). can sibling, one half-brother, one half-sister, nine maternal cousins, and eight paternal cousins, all healthy. The mother had one female and four male siblings, six maternal cousins, and 17 paternal cousins, all healthy. In the generation of the pa¬ tients' grandparents, there were, on the paternal side, two individuals who committed suicide and two others were committed to psychiatric institu¬ tions. On the maternal side, in the same generation, there were two alcoholics. None of these psy¬ chiatric problems was in the direct line of descent of the patients. Case 1.—History.—The prenatal, birth, and early developmental periods of this girl were normal. At age 6 months, she had a febrile illness characterized by diarrhea, vomiting, and sore throat. One week after the onset, there were numerous nonfocal convulsions with staring, generalized bodily twitches, and stiffening of all extremities. On admission to William Beaumont Hospital, the seizures were continuous. She was febrile, comatose, and opisthotonic. Scalp hair was blonde and the texture was fine. The pupils were dilated and fixed to light. The neck was stiff. Tendon reflexes were brisk but symmetrical. Bilateral extensor plantar responses were present. The remainder of the examination was normal. The cerebrospinal fluid contained two lymphocytes and was xanthochromic, and the protein concen¬ tration was 110 mg/100 ml; the sugar content was normal and no organisms were grown on culture. Subdural punctures disclosed the presence of 10 ml of xanthochromic fluid in the right subdural space. She improved rapidly. Three weeks following admission, she was well, except for slight residual weakness of the left arm and leg. Delayed mental development was apparent fol¬ lowing this illness. She had been able to sit un¬ supported at age 5 months, but this milestone was not achieved again until lll/á months. At age 26 months, during a nap on Sept 14, 1954, she de¬ veloped a high temperature and continuous focal seizures occurred, involving the left arm and leg. She was admitted once again. Examination and Course.—She was comatose and in status epilepticus. Cerebrospinal fluid exami¬ nation was normal. Her temperature was 107.8 F (41.7 C) shortly before death occurred, 39 hours after the onset of illness. Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 Postmortem Examination.—The general autopsy examination disclosed no gross abnormalities. There was no microscopic evidence of infection or vascular disease. Moderate fatty changes were present in the liver. The fresh brain weighed 1,240 gm and was normal externally. Coronal sections of the cerebral hemispheres disclosed an old area of encephalomalacia in the left caudate nucleus. This consisted of a cluster of small cysts which meas¬ ured 1 cm in diameter. Histologically, only some strands of glial tissue, small blood vessels with thickened walls, and a few large granular, vacuolated, or hemosiderin-laden macrophages re¬ mained in these cavities. There was an old fibrillary gliosis in the gray matter about them. Occasional degenerated nerve cells impregnated with hematoxylinophilic material (as in cases 2 and 3) were present in this glial scar. No thrombi were found in the arteries and veins here or elsewhere, but the blood vessels were not widely sampled with this possibility in mind. The remainder of the central nervous system, including the spinal cord, appeared normal. The eyes were not examined. Pathological diagnosis: old encephalomalacia in caudate nucleus, cause undetermined. Case 2.—History.—The prenatal jeriod and birth of this girl were not remarkable. She sat at 10 months, crawled at 15 months, and walked at 3 years of age. Toilet training was never accom¬ plished. She was able to speak in only simple sentences at age 7, and mental retardation pre¬ cluded formal education. Illnesses included varicella and numerous recurrent infections of the ears, throat, and lungs. At 6 months of age she had a nonfocal generalized convulsion. Sporadic seizures occurred frequently thereafter. Several brief epi¬ sodes of "bluish discoloration" of the right arm occurred after age 4. In July 1961, at age 6, there was a left hemiparesis following a series of seizures. Subsequently, left-sided focal and Jacksonian seizures occurred, in addition to generalized seizures. On Nov 22, 1962, at age 7%2, a series of left focal seizures was followed by paralysis of the left arm and leg. Three days later, she had improved but she was still unable to walk. At this time the parents first noticed evidence of defective vision. On November 27 she was admitted to William Beaumont Hospital. Physical Examination.—She was irritable and pale. There was no fever. The head measured 53.5 cm in circumference; height, 125 cms (4 ft 1 inch) ; weight 25 kg (56 lb). The scalp hair was light in color, sparse, and brittle. Both skin and hair were exceedingly dry. Bilateral ectopia lentis was present. The left crystalline lens was lying free in the anterior chamber of the eye. Mild livedo reticularis was present in the legs. The remainder of the general examination was normal, except for mild malar erythema. The liver was not en¬ larged. Genu valgum and pes cavus were not present. She appeared and acted severely retarded for her chronological age. In walking, there was circuniduction of the left leg, and movement of the left arm was diminished. The cranial nerves were normal, except for left supranuclear facial weakness. There was moderately severe left hemiparesis, with increased tendon reflexes and an extensor plantar response. Sensory testing was not reliable. Laboratory Studies.—The following were nor¬ mal : blood cell count ; hematocrit ; urinalysis ; urinary phenylpyruvic acid; VDRL (serological test for syphilis) ; serum calcium, phosphorus, sodium, potassium, chloride, bilirubin, alkaline phosphatase, acid phosphatase, cholesterol, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, aldolase, protein-bound iodine; blood sugar ; blood urea nitrogen ; lupus erythematosus cell preparations ; clotting time ; bleeding time ; prothrombin time ; platelet count ; clot retraction ; pe¬ ripheral blood morphology ; sternal bone marrow examination ; chromosome count and morphology ; urinary 17-ketosteroids and 17-hydroxysteroids ; electrocardiogram ; electroencephalogram ; roentgenograms of the chest and skull ; and bone age. Serum lactic dehydrogenase activity was 670 and 1,200 units on two separate occasions (normal, less than 400 units). Serum protein electrophoresis (gm/ 100 ml) ; albumin, 3.6; ai-globulin, 0.16; osrglobulin, 0.76; /3-globulin, 0.52; -globulin, 1.91. After typhoid vaccination, the titer of typhoid H antibodies rose from 1:8 to 1:320. Urinary creatinine excretion, 530 mg, and creatine, 550 mg in 24 hours. Roentgenograms of the lumbar spine and long bones : undermineralized bone structure with thin cortices. Cerebrospinal fluid pressure, 110 mm water; three lymphocytes; protein, 30 mg/100 ml; sugar, 70 mg/ 100 ml; serological tests negative; colloidal gold curve normal. Microscopic examination of scalp hair was normal. Hospital Course.—During the first three weeks the patient was irritable and cried constantly. On Dec 19, 1962, she became febrile, anorectic, and lethargic ; there was evidence of pulmonary and urinary tract infections. Decorticate posture and in¬ creasing stupor supervened on Dec 27, 1962. Coma and spiking fever continued until she died on Jan 6, 1963, aged 7 years, lOJ^ months. Postmortem Examination.-—A perforation, 5 cm in diameter, was present in the fundus of the stomach on the greater curvature, with localized peritonitis in the left subdiaphragmatic space. The left leaf of the diaphragm was necrotic and con¬ tained a 2 cm defect which established a communi¬ cation between the abdominal and the left pleural cavity. Brownish gastric contents were present in the left pleural space with a chemical pleuritis about the lower lobe of the left lung. Bacterial cultures of both lungs revealed the presence of Pseudomonas aeruginosa. The left ventricular myocardium was somewhat hypertrophied. Micro¬ scopic examination disclosed bilateral bronchopneumonia, chronic passive congestion and fatty metamorphosis of the liver, and mesenteric Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 Fig 1 (case 2).— (A) and (5) Infarcts of varying age in frontal and femoral lobes, basal ganglia and internal capsule. (C) Recent encephalomalacia in left frontal lobe. Loss of nerve cells and macrophage formation (hematoxylin and eosin, X 320). (D) Older encephalomalacia, left temporal lobe (hematoxylin and eosin, X 130). lympadenitis. The intima and adventitia of large and medium-sized arteries in the kidney were slightly thickened. Ocular Pathology, Left Eye.—The bulb was normal in size. The lens lay partly in the anterior chamber and displaced the iris centrally. Micro¬ scopically, portions of the superficial corneal epi¬ thelium were missing. There was some acute inflammation in the stroma. A break in Bowman's membrane at one level, covered by normal epithelium, was occupied by elongated cells with irregular nuclei. The filtration angle was reduced on one side by approximation of the iris to the trabecular surface ; the opposing angle was open, but slit-like due to the change in the position of the iris. The trabecular spaces and canal of Schlemm were unchanged. The equatorial portion of the lens occupied and widened the pupillary space. One half of the lens projected into the anterior chamber while the other half abutted upon the anterior hyaloid membrane of the vitreous. The optic papilla unusually prominent. The anterior portion of the disc appeared elongated, possibly due to edema. At the macula the internal limiting membrane of the retina was separated from the underlying struc¬ tures by granular grayish or eosinophilic material. There was minor folding of the lens capsule; the was contents of the lens were not available for exami¬ nation. The ciliary body was reduced in volume and the muscle fibers replaced by fibrous tissue. This change involved not only the meridional fibers but the radial and circular fibers to an even greater extent, particularly on one side. The ciliary proc¬ esses pointed acutely posteriorly and broken short processes of the zonules remained attached between them. Summary of ocular pathology: dislocation of lens into pupillary space and anterior chamber; degeneration (atrophy and fibrosis) of ciliary muscle; focal superficial scar of cornea; acute Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 Fig 2(case 2).—(A) Fresh mural thrombus in leptomeningeal artery of pons. Slight thickening of internal elastic lamina (hematoxylin and eosin, X 130). (B) and (C) Organizing mural thrombi in small leptomeningeal arteries (hematoxylin and eosin, X 320). (D) Focal fibrous intimai thick¬ ening and splitting of elastic membrane (Verhoeff elastic tissue stain, X 130). focal epithelial abrasion and anterior stroma! kcratitis (terminal event). Nervous System, Gross Findings.—The durai sinuses were patent. The brain weight was 1,300 gm, normal for the child's age. No congenital malformations were observed. The leptomeninges and their blood vessels were not remarkable. In the left frontal and both temporal lobes, portions of the cortex felt abnormally soft and tended to split on manipulation. Sections of the cerebral hemispheres revealed these lesions to be large foci of degeneration which extended from the gray matter into the gyral and central white matter (Fig 1, A and B). Many other lesions of the same Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 type were also present bilaterally, in a random pattern, in all of the other lobes. The largest were those in the right temporal lobe and right superior and middle frontal gyri where they ranged up to 8 cm in diameter. Others were much smaller. In the affected regions the cortex was narrowed, finely pitted or cystic, discolored tan or yellowishtan, and poorly dermarcated from the white matter. The latter was pallid or grayish and quite soft. Similar soft, spongy or granular, pale yellowish lesions were found in the caudate nucleus, putamen, globus pallidus, and internal capsule on botli sides (Fig 1, B). Small violaceous discolorations in the cortex and white matter of the left temporal lobe were evidently more recent lesions. There was a loss of clarity of some of the markings in the pontine tegmentum. The cerebellum and spinal cord were normal. Microscopic Examination. Paraffin-embedded material was stained with the hematoxylin and eosin, cresyl violet, Mahon, Bodian, Verhoeff elas¬ tic tissue, and periodic acid-Schiff methods. The first two of these, and Woelke myelin stains were also applied to colloidin sections. Perl's stain for iron and the von Kossa method for calcium were used where indicated. The cerebral lesions observed in the gross had the characteristics of banal infarcts in different stages of evolution and they varied in size. The oldest were marked by total destruction of all neural and neuroglial components and by cavity formation. Amorphous tissue debris, or masses of lipid- and granule-filled macrophages (Fig 1, D), were still present in these regions, however, and some hypertrophied astrocytes were seen at their borders. The final stage of this process, with a disappearance of phagocytes and a fibrillary gliosis, had been reached only in two tiny foci in the frontal cortex and one in the cerebellar white — matter. Where the degeneration was more recent the tissue architecture was partially preserved and the loss of nerve cells and fibers was incomplete. There was an increase in microglia with early macro¬ phage formation (Fig 1, C), and some thickening of the walls of the small blood vessels due to endotheIial cell proliferation. In the cortex and putamen occasional degenerated nerve cells and their proc¬ esses were impregnated with hematoxylinophilic material which stained positively for iron but not for calcium (see also case 3, Fig 3, D). The newest infarcts were in the midbrain and pons where large portions of the gray and white matter of the tegmentum were pallid and rarefied, due to edema. In a few such lesions there was a be¬ ginning infiltration of the tissue by polymorphonuclear leukocytes. In myelin-stained sections these fields were quite pale and individual myelin sheaths were irregularly swollen. Masses of fibrin could be seen in and about the walls of some of the small vessels. Plasmatic fluid filled some of the perivascular spaces and there were occasional petechiae in the neighboring tissue. Similar small fresh infarcts were noted in the cortex of the left cerebellar hemisphere. Beyond the limits of these lesions no tissue al¬ terations were observed except for the finding of small foci of nerve cell loss, and a still-active, large-bodied astrocytosis, in the pyramidal cell layer of the hippocampus, bilaterally, chiefly in the Hi sectors. Nerve cells elsewhere in the gray matter of the brain and spinal cord were un¬ changed in number or structure and myelination in the gray and white matter was judged to be normal. Cerebral Blood Vessels.—In a number of sec¬ tions, one or several leptomeningeal blood vessels were partially or more completely filled with thrombi (Fig 2, A, B, and C). These were found over the cortex of the left frontal and parietal lobes, near the splenium of the corpus callosum, and about the brain stem. It is likely that further histological sampling of the specimen would have revealed others since they could not be seen grossly. Most of the thrombi were in small arteries whose maximum diameters in the sections ranged from about 0.2 to 0.6 mm. An exception was an artery adjacent to the pons which contained fresh mural thrombi and measured nearly 2 mm (Fig 2, A). Only two veins containing thrombi were found, one in the great longitudinal fissure and the other adjacent to the pons. They were larger than the affected arteries and measured 1.6 and 2.0 mm, respectively, at their widest. The more recent arterial thrombi appeared in the hematoxylin and eosin stain as masses of com¬ pact eosinophilic granular or fibrillar material consisting of platelets and some fibrin (Fig 2, A). They were often in contact with the intima along a relatively narrow base and often occupied only a part of the lumen. The nuclei of a few fibroblasts and, rarely, a small crevice, probably representing new capillary formation, could be seen in the mass, but connective tissue fibers were lacking. In most of the affected leptomeningeal arteries the internal elastic lamina and other elements of the vessel wall, examined in hematoxylin and eosin, elastic tissue, periodic acid-Schiff, and phosphotungstic acid-hematoxylin stains presented no structural changes (Fig 2, and C), nor did the veins. One larger artery beneath the pons, however, contained more extensive deposits of mural thrombus and here the subjacent elastic membrane was perhaps slightly thickened (Fig 2, A). In older thrombi, undergoing organization (Fig 2, and C), there were greater numbers of fibro¬ blasts, fine collagen fibers and some small vascular channels containing lymphocytes and a rare macrophage. The free surface of the mural thrombi at this stage was covered by flat endothelial cells, while the base merged into the con¬ nective tissue of the intima. Infrequently the intima was focally thickened in this region and the internal elastic lamina partially frayed out. Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 of numerous leptomeningeal and intraparenchymal vessels which were free of thrombi disclosed no abnormalities of their walls, Examination except for the presence, in one or two small leptomeningeal arteries, of localized widening of the intima due to an increase in fibrous tissue (Fig 2, D). These rare lesions could have represented sites of old organized thrombi merged with the intima. Summary of neuropathological findings: thrombi, organizing, in small leptomeningeal arteries and veins; encephalomalacia, multiple, focal, recent and old, in cerebral cortex and white matter, basal ganglia, thalamus and cerebellum; encephalomalacia, fresh, in midbrain, pons and cerebellum; degeneration of nerve cells and astrocytosis in pyramidal cell layer of hippocampus. Case 3.—History.—The prenatal history and birth of this girl were not remarkable. She sat at recent and 7 months, but did not walk until 21 months. Al¬ though able to help with simple household tasks, she was never able to dress herself and was not toilet-trained. She was never able to speak more than a few words and did not attend school. She was thought to be normal until age 10 months, when there was a series of generalized convulsions, coma, and right hemiparesis. An ex¬ ploratory right parietal craniotomy at William Beaumont Hospital revealed the brain to be swollen and very soft. In an embedded, sectioned biopsy specimen, one large vein in the subarachnoid space, measuring about 5X2 mm was filled and distended by fresh thrombus. Very early invasion of the clot by fibroblasts was in progress. Several small adjacent tributaries of this vessel, and some small intracortical veins, were similarly thrombosed (Fig 3, B). There was mild infiltration of polymorphonuclear leukocytes in the wall of the largest thrombosed vessel, which was no doubt a reaction to the thrombosis, with an accumulation of similar cells, fibrin, lymphocytes, and erythro- cytes in the subarachnoid space. The cortex was in an early stage of hemorrhagic infarction. Nerve cells undergoing acute ischemie necrosis were still present in some fields (Fig 3, B). In other fields, nerve cells had completely disap¬ peared ; the tissue was reduced to structureless debris, contained many petechiae, and was mildly infiltrated by neutrophiles. In slightly older lesions were beginning to appear in the tissue and the walls of the capillaries were hyper- macrophages plastic. Following recovery, the child was subject to recurrent convulsive seizures. Intermittent ectopia lentis was first noted by the parents at 3 years of age. A superficial phlebothrombosis of the left leg" occurred at age 6, in March 1962. She was hos¬ pitalized numerous times for treatment of upper respiratory infections. In November 1962, at age 6H/Ì2, the parents noted frequent displacement of both optic lenses. On November 29, both lenses were found dis- located into the anterior chamber of the eye, producing increased intra-ocular pressure, and she was admitted. Physical Examination.—She was thin and pale. There was no fever. The head measured 52 cm in circumference; height, 123 cm (4 ft 1 inch); weight, 24 kg (53 lb). Scalp hair was sparse and light colored. The hair was easily removed by gentle pulling or brushing. Muscle and soft tissue mass was decreased in all extremities, sug¬ gesting recent weight loss, and bony joints were prominent. Bilateral ectopia lends was present. The remainder of the general examination was normal. Genu valgum, pes cavus, liver enlargement and malar flush were not present. There was nonspecific unsteadiness during tandem walking ; the gait was otherwise normal. The remainder of the neurological examination was normal, except for slight generalized decrease in strength. Reflexes were normal. Laboratory Studies.—The studies recorded as normal in case 1 were also normal in the present case, except for the following : erythrocyte sedi¬ mentation rate (Wintrobe), 38 mm/hour; serum glutamic-pyruvic transaminase, 118 units (normal, less than 50 units) ; serum lactic dehydrogenase, 480 and 697 units on two separate occasions ; and serum aldolase, 15 units (normal, 3 to 8 SibleyLehninger units). Serum protein electrophoresis (gm/100 ml) : albumin, 4.42; «i-globulin, 0.20; asglobulin, 0.20; ^-globulin, 0.50; -globulin, 1.28. Urinary creatinine excretion, 470 mg and creatine, 150 mg in 24 hours. Roentgenograms of the long bones showed generalized demineralization. Cere¬ brospinal fluid and microscopic examination of scalp hair were normal. After typhoid vaccination, the titer of typhoid H antibodies rose from 1 :8 to 1 :160. Hospital Course.—Shortly after admission, an intracapsular lens extraction with peripheral iridectomy was performed on the left to reduce the ocular tension.* The postoperative course was complicated by superficial thrombophlebitis of the left leg. She was discharged on Dec 22, 1962. Subsequently, the parents noted increasing gen¬ eralized weakness, anorexia, and lethargy. She was readmitted on Feb 17, 1963. The physical findings were unchanged except for evidence of severe dehydration and tachycardia. The following day. respirations ceased and she lapsed into coma. Tracheotomy was performed and breathing was maintained by a mechanical respirator. On the third hospital day, decerebrate posturing occurred in response to painful stimuli. Signs of pulmonary edema and infection were present, and death oc¬ curred on Feb 23, 1963, at age 7%2 years. Postmortem Examination.—There was a com¬ plete thrombotic occlusion of the right inferior vena cava distal to the entrance of the renal vessels, as well as thrombosis of the right renal vein extending into the substance of the kidney. * Operation performed by Dr. Martin Lubow. Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 Fig 3 (case 3).—(A) Old hemorrhagic infarct in right cerebral hemisphere dating back six (B) Fresh hemorrhagic encephalomalacia in right parietal lobe (biopsy at age 10 months, of the lesion shown in [A]. Recent thrombosis and mural infiltration by polymorphonuclear leuko¬ cytes, of small cortical vein. Acute ischemie necrosis of nerve cells and hemorrhages in cortex (hematoxylin and eosin, X 320). (C) Right parietal lobe: recent encephalomalacia near the old lesion shown in (A). Ischemie necrosis of cortical nerve cells (hematoxylin and eosin, X320). (D) Right frontal cortex : iron impregnation of nerve cell bodies and dendrites in recent infarct (Perl's iron stain, X 320). monia. Sections of the right kidney showed venous Bacterial cultures of purulent material found in stasis and recent infarction of the renal paren¬ the trachea and bronchi produced an abundant growth of hemolytic Staphylococcus aureus. chyma, as well as numerous small abscesses. Small Microscopic examination revealed an acute cortical infarcts were also found in the left kid¬ tracheitis, bronchitis, and bilateral bronchopneu- ney and there were hemoglobin casts in many of years. Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 Fig 4 (case 3).—Leptomeningeal arteries. (A) Left frontal region: vessel occluded by organ¬ ized thrombus. Its wall is normal (hematoxylin and eosin, X 130). (B) Right frontal lobe: normal elastic lamina in thrombosed artery (Verhoeff elastic tissue stain, X320). (C) Left frontal lobe: small intimai fibrous plaque containing some elastic fibers, in otherwise normal artery (hematoxy¬ lin and eosin, X 320). the collecting tubules. Interstitial infiltrations of acute and chronic inflammatory cells, with abscess formation, were present in pancreas. The remaining thoracic and abdominal viscera were normal. Ocular Pathology.—The Formalin-fixed right eye was slightly shrunken and distorted. It meas- ured 20 mm anteroposteriorly, and 21 X 20.5 mm in the horizontal and vertical meridians, respec¬ tively. The cornea was clear. The iris was brown. The pupil was round, central, and domed forward slightly on the nasal side where it was in contact with the lens. The lens was small, spherical, and Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 dislocated. About half lay behind the nasal side of the iris. Microscopically, small collections of lymphocytes, occasional neutrophiles, and some macrophages containing dark-brown pigment, were present on the endothelium, in the filtration angle and over the anterior aspect of the iris. The base of the iris and contiguous ciliary body were in¬ filtrated by small numbers of lymphocytes and plasma cells. Pigment in the iris, near the pupil, was somewhat disorganized and some occurred in large clumps. The margin of the pupil was dis¬ placed anteriorly. This was not accounted for by any definite membrane. A filamentous, anterior synechia was present on one side, at another level. As noted grossly the lens was displaced and ro¬ tated so that much of the anterior part of the capsule and subcapsular portions were directed toward the base of the iris rather than toward the pupil. The portion of the cortex represented was not remarkable histologically. The equatorial zonular remnants, and those found between, and on the surfaces of, the ciliary processes, appeared unusually fragmented and multidirectional. The ciliary processes, especially on one side, were posteriorly. Separation of the internal limiting membrane of the retina from the inter¬ directed face with the vitreous and from the nerve fiber layer of the retina with accumulations of granular material, were interpreted as postmortem artifacts. Summary of ocular lesions: Dislocation of lens; mild chronic iridocyclitis; pigmentary anomaly of %rh. Nervous System, Gross Findings.—The lumens of the superior sagittal sinus, torcular and first portion of the lateral sinuses were bridged by strands of grayish and tan fibrous tissue but were not occluded. The brain weighed 1,100 gm. At the site of the old craniotomy there was a shallow depression due to loss of brain substance in the posterior portion of the right cerebral hemisphere (Fig 3, A). This was covered by thickened leptomeninges. It measured about 6.5 cm in diameter, and involved most of the right occipital region and adjacent ventroposterior portions of the temporal and parietal lobes. In sections of the brain the cortex and white matter about this lesion were greatly shrunken and their markings obliterated. Yellowish foci of more recent en¬ cephalomalacia ranging from a few millimeters up to 1.0 cm in size could be seen in the gray and white matter of both frontal lobes. One, in the white matter, was cystic. A small artery in the depths of the right superior frontal sulcus was occluded. Dusky hemorrhagic lesions, 2 cm in diameter, were found in the ventral parts of the cortex and central white matter of the left cerebellar hemisphere with smaller ones on the right. The spinal cord was normal. Microscopic Examination.—The staining pro¬ cedures used were the same as in case 2. Many small and large infarcts, in addition to those ob¬ served grossly, were present in the cerebral hemi- spheres. Their histological features were similar to those in case 2. The most extensive lesions were in the cerebral cortex and white matter where all lobes were involved, and where they were often several centimeters in diameter. Others, in the putamen, cerebellum, pons and upper medulla were generally smaller. Only in the cerebellum were the lesions hemorrhagic. Many of the infarcts were quite recent, as indicated by the presence, in the cortex, of nerve cells undergoing acute ischemie necrosis (Fig 3, C), and by infiltrations of the perivascular spaces and degenerating tissue by polymorphonuclear leukocytes. Early lesions in the internal capsule, cerebral cortex pons and medulla contained hypereosinophilic, swollen, degenerating axons. In older infarcts no nerve cells remained except for a few which could be identified by their ferruginized bodies and dendrites (Fig 3, D). There was considerable microglial activation and phagocytic infiltration in the affected zones, and a proliferation and hypertrophy of astrocytes toward their margins. Foci of coagulative necrosis con¬ taining eosinophilic parenchymal debris, and strewn with nuclear fragments and particles, occasionally occurred in and near these areas. The only very old infarct was that in the pos¬ terior portion of the right cerebral hemisphere which had been biopsied about six years before death. The cortex and white matter in this region were atrophied, had lost all nerve cells and fibers and were composed chiefly of masses of glial fibers and some shrunken astrocytes with sparse accumu¬ lations of hemosiderin-laden macrophages. Many cystic spaces were present in this glial scar. Signs of selective degeneration were apparent bilaterally in the pyramidal cell layer of the hippocampus. Numerous nerve cells had dis¬ appeared and there was a moderate astrocytic proliferation. Many of the remaining neurones were still in the course of degeneration and were undergoing acute ischemie necrosis. No develop¬ mental defects were observed in the cortex or elsewhere. Some pallor of myelin staining in the cerebral white matter was apparent in many of the sections but this appeared to be a part of, or secondary to, the ubiquitous encephalomalacic lesions, rather than to a disorder of myelination . per se. Cerebral Blood Vessels.—Arterial thrombi, old and recent, similar to those in case 2, were ob¬ served in many small leptomeningeal arteries, particularly in the frontal lobes (Fig 4, A and B). Most of these vessels were of the order of 0.2 to 0.5 mm in diameter, the extremes being 0.1 and 0.9 mm. Some contained only small mural thrombi while others were more or less completely ob¬ structed by large masses undergoing fibrous or¬ ganization. These were broadly adherent to the intimai surface or were attached to it at several points. In organizing thrombi there were occasional new capillaries, small collections of macrophages, and in one instance, some granules of calcific ma- Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 1.5 0.6 0.2 0 LO 0.6 0.2 t I ~ CH2 I CH? HO-CH2 + CHNHj I CHNH, z I I crsTA THIONINE — SERINE HOMOCYSTEINE HS- CH2 CH2 C 2 SYNTHETASE\ COOH crSTArmONASE (pyndaxal CH2 CHNH2 CHNH2 I phosphate) COOH tpyridoxal COOH phosphate! HOMOSERINE CYSTATHIONINE COOH CYSTEINE 11 ÇH3 S CH2-S-SCH2 I I ÇH2 CHNH,* CH2 ® CHNH,* COOH I I COOH METHIONINE I SH ATP COOH CH, I Z CHNH, * I COOH Fig 6.—Metabolic pathways of methionine and homocysteine. C-0 I COOH •Í-KETO-YMETHIOL BUTYRIC ACID HOMOCYSTINE Skeletal Changes.—Genti valgum, pes cavuSj kyphosis, scoliosis, and arachnodactyly were prominent features of cases reported from Great Britain.4 The only skeletal ab¬ normality in the present cases was roentgenographic evidence of thinning of cortical osseous tissue of spine and long bones, con¬ sistent with a mild degree of osteoporosis. Convulsive Disorder and Mental Retarda¬ tion.—In addition to the cerebral manifesta¬ tions of vascular occlusion, these children have other evidence of brain disease. Psychomotor maturation is delayed in all cases, mental retardation is severe, and nonfocal convulsions have occurred in half of the pa¬ tients. In the present patients, seizures were difficult to control at the outset but subse¬ quently responded to moderate doses of con¬ ventional anticonvulsant drugs. Pattern of Inheritance.—The cases thus far have included several sets of siblings.1·4·16 Both sexes have been affected, but the parents have always been clinically normal. Consanguinity has been present in some cases.4 The clinical evidence suggests an autosomal, recessive gene, and low activities of cystathionine synthetase were found in liver biopsies of hétérozygotes by Finkelstein and his associates.8 The enzyme was not de- tected in normal leukocytes, and it has not yet been possible to detect the heterozygous carrier by a simple procedure, but the re¬ sponse of the mothers in the present family and others 3·16 to the ingestion of methionine, suggests that some test less involved than liver biopsy may ultimately be feasible. Carson and associates 2 commented on the high incidence of psychiatric disorder in maternal relatives of their cases 1 and 2. The paternal pedigree of the present family con¬ tains two cases of suicidal death and two relatives who are confined to mental hos¬ pitals. Biochemical Abnormality.—The chemical data obtained in the present case have been obtained by methods patterned after those of Gerritsen et al.11 They provide strong evidence that the unknown com¬ pound is homocystine. There was insufficient material for the isolation of large quantities of the amino acid but in a similar case, Field and his associates did obtain enough for elemental analysis.3 The appearance of homocystine in both blood and urine suggests that there is a block in the further metabolism of this compound. This is reinforced by the presence of inThe Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 creased methionine concentrations in the plasma and cerebrospinal fluid 3·4·16 of some patients. (Failure to detect homocystine in plasma and cerebrospinal fluid in some cases is probably due to technical factors.) The pertinent metabolic pathways are out¬ lined in Fig 6. There are only three enzymes involved in the major pathway. The first is the methionine-activating enzyme which, in the presence of adenosine triphosphate and methionine, catalyzes the formation of S-adenosyl methionine, in which the methyl group is activated for transfer as a onecarbon unit. The remainder of the carbon chain forms homocysteine, which is easily oxidized in a side reaction to the correspond¬ ing disulfide, homocystine. In the presence of the second enzyme, cystathionine synthetase, homocysteine and serine are linked to form the thioester, cystathionine. This is subsequently followed by a splitting enzyme to form cysteine and homoserine. Because of the accumulation of both homocysteine and methionine, it may be as¬ sumed that the block must lie in the forma¬ tion of cystathionine. This has been demonstrated by Mudd and his associates,23 who developed a very sensitive assay, em¬ ploying radioactive labeled substrate. They showed that methionine activating enzyme was present in normal amount in a liver homogenate of one patient, but cystathionine synthetase was absent. Relation of the Biochemical Defect to the Clinical Syndrome.—The relationship of the biochemical abnormality to the clinical mani¬ festations is not known. As indicated above, the basis for the abnormal tendency to thrombosis is uncertain, and in the cases re¬ ported here, there were no morphological changes of the nerve cells or fibers which could be ascribed directly to the metabolic disorder. The degeneration of nerve cells in the pyramidal cell layer of the hippocampus in cases 2 and 3 was probably a consequence of the repeated convulsions. Estimation of the adequacy of myelination in the cerebral and cerebellar hemispheres was rendered difficult by the presence of the numerous, often large, encephalomalacic lesions. Poorly demarcated areas of slight pallor of the white matter, in myelin stains, were noted at the borders of these lesions. This change, however, appeared to be a consequence of, or a part of, the infarction. Where it was possible to examine the white matter inde¬ pendently of the encephalomalacia, myelination seemed to be normal, as it was in the fiber tracts of the brain stem and spinal cord. Cases without cerebral infarcts would be more suitable for pathological study than those complicated by vascular lesions. It is unlikely that the multiple thromboses and cerebral infarcts in these children wholly account for the convulsive seizures and mental impairment, although they may have been a contributory factor. In case 1 there was only a single small infarct in the caudate nucleus, and in case 2 there were no lesions sufficiently old and extensive to explain the early onset of the mental defect and re¬ peated convulsions. In case 3 the large in¬ farct in the right cerebral hemisphere no doubt preceded, and perhaps initiated, the first episode of convulsions, but the other le¬ sions in the brain would seem to have devel¬ oped later than the period when the mental deficit was first noted. It may be assumed, therefore, that the metabolic defect itself is responsible for some of the more disabling symptoms, par¬ ticularly the mental retardation and con¬ vulsive disorder. How this comes about is uncertain. Cystathionine is normally present in cerebral tissue,29 but this compound is lacking in the brains of affected in¬ dividuals,2·13 a finding consistent with the block postulated. It is not known whether a deficiency of this compound, or of cysteine, could be responsible for the clinical mani¬ festations. There is also another possible explanation, that homocysteine, or a by¬ product, accumulates in toxic amounts. Klavins 17 fed homocystine in large amounts to rats and produced a variety of patho¬ logical changes in different organs, but not in the brain or in the aorta and other blood vessels. Which of these alternatives is correct has important therapeutic implications. As sug¬ gested by Mudd et al,23 a deficiency of cystathionine or cysteine might be overcome by dietary supplements, but if there is a toxic accumulation, dietary restriction would be Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015 necessary, and methionine is an essential amino acid. Neither approach has yet re¬ ceived an adequate trial. As in phenylketonuria, it would probably be necessary to start any dietary therapy in the neonatal period. Summary A family affected by homocystinuria has been described, in which three children had symptoms. About 20 cases have been re¬ ported since this condition was first de¬ scribed in 1962. The children in this family had all of the major clinical features : severe mental re¬ tardation, convulsive disorder, cerebrovascular occlusion, fine, fair hair, pale skin, and ectopia lentis. At autopsy, there were many infarcts of varying age in the cerebral hemispheres, brain stem, and cerebellum, due to the presence of thrombi in arteries and, occasionally, veins. No abnormalities were present in the walls of cerebral vessels which could be shown to precede thrombus formation. Thrombosis of the inferior vena cava and renal vein was present in one case. The abnormal amino acid was identified as homocystine by column chromatography under varying conditions, by paper chroma¬ tography in different solvents and by ap¬ propriate changes with oxidizing and reducing agents. Homocystine was present in the blood and urine, and methionine was also present in in¬ creased amounts in the plasma of one pa¬ tient. These abnormalities are compatible with lack of cystathionine synthetase, an enzymatic defect which has been directly demonstrated by others. The disease is probably transmitted in an autosomal recessive pattern. The clinically normal mother excreted increased amounts of homocystine after the ingestion of methionine. In a recent article Schimke et al31 described 38 individuals who excrete homocystine in the urine. Their studies in¬ dicate that homocystinuric persons are not necessarily mentally retarded. Supported in part by research grants NB 01620-06, 07, and NB 3102, Clinical Research Center grant B-3359, and Neuropathology Training grant NB 5062-09, from the Na¬ tional Institute of Neurological Diseases and Blindness, US Public Health Service. The postmortem findings and some histological sections in case 1 were made available through the William Beaumont General Hospital, El Paso, Tex. The postmortem examina- lions in cases 2 and 3 were performed by Lt. Col. Proctor L. Child, of the same hospital, who submitted the brains to us for examination and provided the data on the general patho¬ logical findings. The ophthalmic pathology was described by Dr. L. L. Calkins, Kansas City, Kan. Dr. Perry G. Rigby performed the chromosome studies. Mrs. Barbara Arnold assisted in the biochemical studies. REFERENCES 1. Arnott, E.J., and Greaves, D.P.: Ocular Involvement in Homocystinuria, Brit J Ophihal 48:688-689, 1964. 2. Brenton, D.; Cusworth, D.C.; and Gaull, G.E.: Homo- cystinuria: Biochemical Studies of Tissue, With Comparito Cystathioninuria, Pediatrics 35:50-56, 1965. 3. Carson, N.A.J., et al: Homocystinuria: A New Inborn Error of Metabolism Associated With Mental Deficiency, son Arch Dis Child 38:425-436, 1963. 4. Carson, N.A.J., et al: Homocystinuria: Clinical and Pathological Review of Ten Cases, J Pediat 66:565-583, 1965. 5. Carson, N.A.J., and Neill, D.W.: Metabolic Abnor malities Detected in a Survey of Mentally Backward Individuals in Northern Ireland, Arch Dis Child 37:505-513, 1962. 6. Dr\l=e'\ze,A.; Moore, S.; and Bigwood, E.J.: On the Desalting of Solutions of Amino Acids by Ion Exchange, Anal Chim Acta 11:554-558, 1954. 7. Field, C.M.B., et al: Homocystinuria: A New Disorder of Metabolism, abstracted 10th International Congress Paediatrics, Lisbon, 1962, p 274. 8. Finkelstein, J.D., et al: Homocystinuria Due to Cystathionine Synthetase Deficiency: The Mode of Inheritance, Science 146:785-787, 1964. 9. Fischl, J.; Sason, I.; and Segal, S.: A Rapid Spot Test for the Determination of Cystinuria and Amino Aciduria, Clin Chem 7:674-677, 1961. 10. Frimpter, G.W.; Haymowitz, A.; and Horwith, M.: Cystathioninuria, New Eng J Med 268:333-339, 1963. 11. Gerritsen, T.; Vaughn, J.G.; and Waisman, H.A.: The Identification of Homocystine in the Urine, Biochem Biophys Res Comm 9:493-496, 1962. 12. Gerritsen, T., and Waisman, H.A.: Homocystinuria, an Error in the Metabolism of Methionine, Pediatrics 33:413\x=req-\ 420, 1964. 13. Gerritsen, T., and Waisman, H.A.: Homocystinuria: Absence of Cystathionine in the Brain, Science 145:588, 1964. 14. Gibson, J.B.; Carson, N.A.J.; and Neill, D.W.: Pathological Findings in Homocystinuria, J Clin Path 17: 427-437, 1964. 15. Harris, H.; Penrose, L.S.; and Thomas, D.H.H. : Cystathioninuria, Ann Hum Genet 23:442-453, 1959. 16. Kennedy. C.; Shih, V.E.; and Rowland, L.P.: Homocystinuria: A Report in 2 Siblings, J Pediat to be published. 17. Klavins, J.V.: Pathology of Amino Acid Excess: 1. Effects of Administration of Excessive Amounts of SulphurContaining Amino Acids; Homocystine, Brit J Exp Path 44:507-515, 1963. 18. Komrower. G.M., and Wilson. V.K.: Homocystinuria, Proc Roy Soc Med 56:996-997, 1963. 19. Levin, B.; MacKay, H.H.M.; and Oberholzer, V.G.: Arginosuccinic Aciduria, Arch Dis Child 36:622-632, 1961. 20. MacDonald, D., et al: Homocystinuria, Thrombosis and Blood Platelets. Lancet 1:745-746, 1964. 21. McKusick, V.A.: Heritable Disorders of Connective Tissue, St. Louis: C. V. Mosby Co., 1960. 22. Menkes, J.H., et al: A Sex-Linked Recessive Disorder With Retardation of Growth, Peculiar Hair, and Focal Cerebral and Cerebellar Degeneration, Pediatrics 29:765\x=req-\ 779, 1962. 23. Mudd, S.H.. et al: Homocvstinuria: An Enzymatic Defect, Science 143:1443-1445. 1964. 24. Perry, T., and Jones, R.T.: The Amino Acid Content of Human Cerebrospinal Fluid in Normal Individuals and in Mental Defectives, J Clin Invest 40:1363-1372, 1961. 25. Rowland, L.P.: Unpublished data. 26. Schram. E.; Moore, S.; and Bigwood, E.J.: Chromatographic Determination of Cysteine as Cysteic Acid, Biochem J 57:33-37, 1954. 27. Smith, I. (ed.): Chromatographic and Electrophoretic Techniques, London: Heinemann. Ltd., 1960. 28. Spackman, D.H.; Stein, W.H.; and Moore, S.: Automatic Recording Apparatus for Use in the Chromatography of Amino Acids. Anal Chem 30:1190-1206, 1958. 29. Tallan, H.H.; Moore, S.; and Stein. W.H.: L-Cvstathionine in Human Brain, J Biol Chem 230:707-716, 1958. 30. White, H.H., et al: Homocystinuria, Trans Amer Neurol Assoc 89:24-27, 1964. 31. Schimke, R., et al: Homocvstinuria: Studies of 20 Families With 38 Affected Members, JAMA 193:711-719, 1965. Downloaded From: http://archneur.jamanetwork.com/ by a University of Arizona Health Sciences Library User on 05/25/2015