This was a 4-month-old male child, born of non-consanguineous marriage, as a 4th child with normal birth history. His height was 63 cm (which is at 50 percentile) weight 5.2 kg (less than 5 percentile) and Head circumference 40 cm. Developmental milestones (social smile and head control) were normal till present episodes when he suffered an acute viral illness characterized by loose motions, drowsiness. He was admitted for acute gastroenteritis. Child was drowsy; hypotonia, brisk deep tendon reflexes and plantars were extensors. On the 3rd day of admission, he developed generalized tonic clonic convulsion. The child’s ABG, S. calcium and electrolyte were normal. CSF study was also normal. Convulsions were controlled with antiepileptic drugs such as phenytoin and Phenobarbitone, but child had lost the entire milestone. Hence, CT brain was done, which showed widening of sylvian fissures. On the basis of CT brain and MRI brain (Figs. 1a, 1b and 1c), which revealed features characteristic of GA I. MRI T1-weighted axial imaging showed fronto-temporal atrophy and bat-wing dilatation of the sylvian fissures. MRI T2- weighted axial imaging showed hyperintense signal abnormality in both putamen and in the fronto-parietal deep white matter.

Fig. 1a : CT scan brain : Widened Sylvian fissure	Fig. 1b : MRI brain : Axial T1- weighted image showing bilateral widening of Sylvian fissure

There was no hypoglycaemia or hyperammonaemia The plasma amino acids were done by thin layer Chromatography (TLC), which were normal. Urinary amino acids done by TLC revealed a generalized aminoaciduria with prominent spots of histidine, lysine and alanine being detected. Urinary organic acid by TLC showed a prominent spot for Glutaric acid. Urine analysis by gas chromatography-mass spectroscopy (GC-MS) revealed a marked excretion of glutaric acid and trace excretion of 3-hydroxy glutaric acid. The diagnosis of GA-I was confirmed on the basis of characteristic neuroimaging and biochemical studies.

Child was advised a lysine and tryptophan free diet (sagokangi and arrow root powder) with supplementation with riboflavin and L-carnitine after which the child improved symptomatically.

GA-I is a rare metabolic neurodegenerative disease, which has a “varied” presentation. In GA-I the deficiency of the enzyme Glutaryl CoA dehydrogenase (GCDH) results in excessive accumulation of these metabolites in various tissues and body fluids.1 Reports of asymptomatic older children and adults with neuroimaging and biochemical abnormalities characteristic of GA-I have also been published.5,6 The disease is inherited as an autosomal recessive trait. Mutations of the GCDH gene on chromosome 19 have been implicated in the causation of GA-I.7

Fig. 1c : MRI brain : Axial T2-weighted image displaying bilateral widened Sylvian fissure

GA-I has protean manifestations. The usual age of presentation for GA-I is 6 months to 2 years of life.1,5 Metabolic derangement, which is the hallmark of organic acidurias, is minimal or absent even during acute symptomatic episodes.5 Hence, such cases are diagnosed as acute encephalitis, Reye syndrome or vaccine induced encephalopathy. A report of asymptomatic adults with biochemical abnormalities characteristic of GA-I adds to the clinical variability with which the disease can present.1,5 When characteristic features of GA-I are present, the disorder can remain undiagnosed. This is not only because the disorder is rare and its awareness is far from optimum but also because the abnormal metabolites are detected in the urine intermittently or not at all even during acute metabolic crisis.1,8 Brismar and Ozand9 reviewed 64 CT or MRI of the brain in GA I and found that brain atrophy of hypoplasia was seen in 61% and white matter changes in 51% of patients, open opercula and often wide CSF spaces anterior to the temporal lobes were seen in 93%. Similarly, our patient’s MRI also shows cortical atrophy and open opercula. Metabolic disorders such as GA II, respiratory chain disorder, branched chain organic acidurias as well as riboflavin deficiency and valproate therapy have been associated with increased urinary glutarate excretion.8 After initiation of treatment consisting of low-protein diets, special formulas low in Lysine and Tryptophan and supplements of riboflavin and L-carnitine, a few patients may show slight improvement, but long-term prognosis remains unfavourable.1,5 Valproate has also been recommended because of its inhibitory action on the enzyme GABA transaminase.9

If GA-I confirmed, genetic counselling is appropriate and the possibility of prenatal diagnosis can be offered