Metab Brain Dis (2017) 32:967–970 DOI 10.1007/s11011-017-0005-5 SHORT COMMUNICATION Novel magnetic resonance imaging findings in a patient with short chain acyl CoA dehydrogenase deficiency Shwetha Chiplunkar 1,2 & Parayil Sankaran Bindu 2,3 & Madhu Nagappa 2,3 & Bobby Baby Panikulam 3 & Hanumanthapura R Arvinda 4 & Periyasamy Govindaraj 2,3 & MM Srinivas Bharath 5 & Narayanappa Gayathri 2,6 & JN Jessiena Ponmalar 2 & Pavagada S Mathuranath 3 & Sanjib Sinha 3 & Arun B. Taly 2,3 Received: 9 December 2016 / Accepted: 29 March 2017 / Published online: 3 April 2017 # Springer Science+Business Media New York 2017 Abstract Reports on magnetic resonance imaging findings in patients with short chain acyl –Coenzyme A dehydrogenase (SCAD) deficiency, an autosomal recessive disorder caused by mutations in the acyl-Coenzyme A dehydrogenase (ACADS), are limited. Many asymptomatic carriers of ACAD variants have also been described necessitating careful evaluation of clinical and biochemical findings for an accurate diagnosis. Here we report a an infant with short chain acyl –Coenzyme A dehydrogenase (SCAD) deficiency diagnosed based on the characteristic biochemical findings and confirmed by genetic testing. He presented with refractory seizures and neuro regression at 4 months of age. His metabolic work up revealed elevated butyryl carnitine in plasma and ethyl malonic acid in urine. Magnetic resonance imaging of the brain showed cortical and basal ganglia signal changes with cortical swelling. Serial scans showed progression of the lesions resulting in cystic leukomalacia with brain atrophy. Exome sequencing revealed a novel homozygous nonsense variation, c.1146C > G (p.Y382Ter) in exon ten of ACADS which was further validated by Sanger sequencing. Both parents were The original version of this article was revised: The author name Shwetha Chiplunkar was incorrectly written. Author given name BShwetha^ was missing. * Parayil Sankaran Bindu drpsbindu@yahoo.co.in Pavagada S Mathuranath psmathu@yahoo.com Sanjib Sinha sanjib_sinha2004@yahoo.co.in Shwetha Chiplunkar shwetha.chiplunkar@gmail.com Arun B. Taly abtaly@yahoo.com Madhu Nagappa madhu_nagappa@yahoo.co.in 1 Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India 2 Neuromuscular Laboratory-Neurobiology Research Centre, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India 3 Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India 4 Department of Neuroimaging & Interventional Radiology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560029, India Narayanappa Gayathri gayathrin12@rediffmail.com 5 Department of Neurochemistry, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India JN Jessiena Ponmalar jesse.jey89@gmail.com 6 Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India Bobby Baby Panikulam drbbpme7722@gmail.com Hanumanthapura R Arvinda aravind.radiology@gmail.com Periyasamy Govindaraj pgovinth@gmail.com MM Srinivas Bharath thathachar@rediffmail.com 968 Metab Brain Dis (2017) 32:967–970 heterozygous carriers. Follow up at 15 months showed gross psychomotor retardation and refractory seizures despite being on optimal doses of anti-epileptic medications, carnitine and multivitamin supplementation. This report expands the phenotypic and genotypic spectrum of SCAD deficiency. Keywords Short chain acyl -coenzyme A dehydrogenase (SCAD) deficiency . ACAD . MRI . Cystic leukomalacia . Basal ganglia Introduction Short chain acyl Co-A dehydrogenase (SCAD) is a vital enzyme catalysing beta oxidation of short chain fatty acids in the mitochondria. It converts four or six carbon compounds to 2-enoylCoA (van Maldegem et al. 2010) and is encoded by ACADS localised to chromosome 12q24.31. SCAD deficiency secondary to mutations in the ACADS is rare and has variable clinical manifestations. Phenotypes range from developmental delay, hypotonia, hypoglycaemia, abnormal behavioural and seizures to asymptomatic individuals identified by metabolic screening (van Maldegem et al. 2006). Due to this extreme variability, the role of SCAD deficiency in causing disease is a matter of debate. Besides, its inclusion in new-born screening panel is questioned as identification of SCAD deficiency does not necessarily mean that the patient will develop symptoms. Nevertheless, it is important to understand the clinical profile of SCAD deficiency for identification of symptomatic and asymptomatic individuals and initiate early intervention, prenatal diagnosis and genetic counselling. Pattern of abnormalities on brain Magnetic Resonance Imaging (MRI) plays an important role in the diagnosis of metabolic disorders particularly when it is the earliest investigation available to the clinician. Data on brain MRI observations in children with SCAD deficiency is limited. In this report, we describe the brain MRI findings in a four-months-old infant with SCAD deficiency and novel variation in ACADS. Case report Proband was the only child of consanguineously married couple (second cousins) from south India (Fig. 1a). Family history was negative for neurological disorders. Ante-natally, the mother developed pregnancy induced hypertension during eighth month of gestation and was treated with anti-hypertensives. He was born at term by lower segment caesarean section, indication being meconium stained amniotic fluid and suspected meconium aspiration. He cried soon after birth, weighed 3.25 kg and had no other perinatal events. From third month of life, he developed seizures characterised by incessant cry and gaze deviation to the right. Seizures remained refractory to anti-epileptic medications from onset. At presentation to our clinic at four months of age, he had recurrent right focal seizures while on two anti-epileptic drugs at optimal doses with associated developmental delay. He had not attained neck control or mother regard. Examination revealed an alert child with nasogastric tube in situ. His weight was six kg (10th centile for age) and head circumference 41 cm (25th centile for age). There were no dysmorphic features or organomegaly. He could not fix or follow light or localize sound. He had normal ocular fundi, generalised Metab Brain Dis (2017) 32:967–970 ƒFig. 1 Pedigree chart shows consanguinity within the family (a). Brain MRI done at four months of age (b-d) shows diffuse hyperintensities in bilateral basal ganglia (arrows), periventricular white matter and cerebral cortices with gyral swelling in axial FLAIR (b), axial T2 W (c), and coronal T2 W (d) sequences. There is asymmetric involvement of cerebral cortices, with left side being more affected than the right. Brain MRI at 4.5 months of age (e-g) shows: increase in hyperintensities in the affected areas in axial T2 W (f) and coronal T2 W (g) sequences. There is inversion in frontal white matter in axial FLAIR (e-arrow heads). Cerebral edema has reduced compared to previous scan and extra-axial CSF spaces over the cerebral convexities are increased. Brain MRI at nine months of age (h-m) shows subdural bleed along left cerebral convexity along with asymmetric multi-cystic encephalomalacia in bilateral basal ganglia and left thalamus in axial FLAIR (h-arrows), axial T2 W (iarrows), and coronal T2 W (j-arrows) sequences. Bilateral cerebral white matter also shows encephalomalacia with an anteroposterior gradient (arrow heads). Focal areas of restricted diffusion are noted on ADC (k) and DWI (l) sequences (arrows). There is involvement of bilateral dentate nuclei and portions of peri-dentate white matter of cerebellum (marrows). Electropherogram shows c.1146C > G variation in patient in homozygous state (n), while being present in heterozygous state in father (o) and mother (p). Conservation of amino acid tyrosine at position 382 of ACADS in different species (q) hypotonia and normal muscle stretch reflexes. He was followed up to the age of one year. Seizures remained refractory to treatment with multiple anti-epileptic drugs and global delay persisted. He also received high dose vitamins along with levocarnitine. Metabolic screening revealed elevated serum lactate (35, ref.: 4.5–20 mg/dl), normal serum ammonia, hepatic and renal function tests. Concurrent serum pyruvate levels could not be obtained. Tandem mass spectrometry revealed normal amino acid profile and elevated butyryl carnitine. Urine organic acids analysis showed an eight fold elevation of ethyl malonic acid. Surface electroencephalogram (EEG) showed intermittent, generalised epileptiform discharges with background slowing. Brain MRI done at four months of age (Fig. 1b-e) showed diffuse hyperintensities in bilateral basal ganglia, periventricular white matter and cerebral cortices with gyral swelling. Brain MRI at 4.5 months of age (Fig. 1f-g) showed an increase in hyperintensities in the affected areas with inversion in frontal white matter. Cerebral edema had reduced compared to previous scan and extraaxial CSF spaces over the cerebral convexities were increased. Brain MRI at nine months of age (Fig. 1h-m) showed subdural bleed along left cerebral convexity along with asymmetric multi-cystic encephalomalacia in bilateral basal ganglia and left thalamus. Bilateral cerebral white matter also showed encephalomalacia with an anteroposterior gradient. Focal areas of restricted diffusion were noted (Fig. 1k-l). There was also involvement of bilateral dentate nuclei and portions of peri-dentate white matter of cerebellum (Fig.1m). Based on the clinical profile and involvement of cortical and deep grey on MRI, a diagnosis of progressive neuronal 969 degeneration possibly arising from mitochondrial dysfunction was considered. Histopathological studies of quadriceps femoris muscle biopsy revealed preserved architecture with polygonal fibres. Enzyme histochemistry revealed normal mosaic pattern; no ragged red, ragged blue or COX deficient fibres. Respiratory chain enzyme assays by spectrophotometry showed normal activity of all enzyme complexes. Sequencing of POLG1 did not reveal any pathogenic variations. Subsequently exome sequencing was performed using illumina sequencing platform and the gene panel consisted of 6440 genes inclusive of all nuclearencoded mitochondrial genes that are strongly associated with a disease on online medelian inheritance in man (OMIM). This revealed a novel homozygous nonsense variation at c.1146C > G in exon ten of ACADS (Acyl CoA Dehydrogenase) which was further validated by Sanger sequencing (Fig.1n). Both parents were heterozygous carriers (Fig.1o and p). This variation was predicted to result in a stop codon with premature truncation of the protein at codon 382 (p.Y382Ter). The p.Y382Ter variant was not found in the 1000 genome and ExAC databases. This variant was predicted to be damaging by Sorting Intolerant From Tolerant (SIFT) and Mutation Taster. The region is conserved across species [Fig. 1q]. Discussion ACADS is located on chromosome 12q24.31 and encodes for SCAD. It is a 412 amino-acid mitochondrial flavoprotein that belongs to beta oxidation spiral of fatty acid metabolism. It converts four or six carbon compounds to 2-enoyl-co A (Naito et al. 1989). A variation in the ACADS is usually reported as pathogenic if there is a missense or nonsense variant in homozygous state or in trans with variants confering disease susceptibility. Hence it is described as mutation/mutation or mutation/variant or variant/variant state (van Maldegem et al. 2006). ACADS is known to cause widely varying phenotypes from asymptomatic carriers to symptomatic seizures, developmental delay, hypotonia and behavioural abnormalities (van Maldegem et al. 2010). The pathomechanism of neural toxicity caused by ACADS variation is not known. There are suggestions that SCAD deficiency is a disorder of protein mis-folding but this awaits more validation (Pedersen et al. 2008). Biochemical diagnosis of SCAD deficiency is established by demonstrating elevated butyryl carnitine in blood and ethyl malonic acid in urine (Gallant et al. 2012). Many countries have included this in the new-born screening panel leading to identification of several neonates and family members. A limited number of follow up studies of such asymptomatic infants and family members have shown ambiguous outcomes, with some developing symptoms and others remaining asymptomatic for years (van Maldegem 970 et al. 2010). Further, it has been hypothesised that medium chain acyl Co A dehydrogenase (MCAD) is able to alter substrate specificity and execute the functions of SCAD, thereby explaining the occurrence of asymptomatic carriers (Bennett 2010). Despite the arguable differences, there are documented reports on clinical characterization of SCAD deficiency with ACADS variations (Reddy and Sujatha 2011; Jiang et al. 2012; Lampret et al. 2015). Our patient presented with early onset refractory seizures, hypotonia, and elevated of butyryl carnitine and ethyl malonic acid with a homozygous nonsense variant in ACADS which would suggest a SCAD deficiency. There are a few reports describing the clinical manifestation of SCAD deficiency. Amendt et al. reported two neonates, one with transient metabolic acidosis with impending complications who was rescued with administration of glycine and maintained well thereafter and another with metabolic acidosis, hepatic decompensation and death (Amendt et al. 1987). Similarly, there are reports of neonatal hypotonia and bronchopneumonia (Sewell et al. 1993), severe myopathy with carnitine deficiency (Coates et al. 1988), isolated speech delay with hyperactivity and a neonate with spasticity and nystagmus (Bhala et al. 1995). Literature regarding brain MRI in SCAD deficiency are further limited. Reddy et al. reported normal MRI of brain in their patient (Reddy and Sujatha 2011). In contrast, our patient had striking abnormalities that evolved in serial scans. Three serial MRIs done at three, four and twelve months of age revealed diffuse white matter hyperintensities and basal ganglia lesions with restricted diffusion progressing into severe cystic leukomalacia and atrophy with sub-dural collection. These features may be seen as a consequence of any insult to the brain resulting in acute energy failure including hypoxic ischemic encephalopathy (Van der knaap and valk 2005). Hence it is proposed that this variant, p.Y382Ter, could be pathogenic causing energy deficient state in this child resulting in such an MRI finding. At least 70 different variations in ACADS have been reported. Many of them await functional validation. Certain mutations like p.R171W (c.511C > T) and p.G209S (c.625G > A), in homozygous state, are believed to confer susceptibility to disease (Gregersen et al. 2001). Our patient harboured an unreported variation that was predicted to generate a truncated protein. The asymptomatic parents, being heterozygous carriers of the same variant, further supported the probable pathogenicity of the variant in this child. In conclusion, we report the magnetic resonance imaging findings in an infant with refractory seizures and delayed development with biochemical evidence of SCAD deficiency and novel homozygous variation in ACADS. Phenotypic and genotypic description of more patients are needed for the accurate characterization of this disease. Metab Brain Dis (2017) 32:967–970 Acknowledgements This study was supported by a grant (Grant no. 54/9/2012-HUM-BMS) from the Indian Council for Medical Research(ICMR), Government of India. Compliance with ethical standards Conflict of interest The authors report no conflict of interest. References Amendt BA, Greene C, Sweetman L, Cloherty J, Shih V, Moon A et al (1987) Short-chain acyl-coenzyme A dehydrogenase deficiency clinical and biochemical studies in two patients. J Clin Invest 79(5):1303–1309 Bennett MJ (2010) Pathophysiology of fatty acid oxidation disorders. J Inherit Metab Dis 33(5):533–537 Bhala A, Willi SM, Rinaldo P, Bennett MJ, Schmidt-Sommerfeld E, Hale DE (1995) Clinical and biochemical characterization of short-chain acyl-coenzyme a dehydrogenase deficiency. 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