A 1-year-old boy with uneventful perinatal history, non-consanguineous parentage presented with global developmental delay. Family history was not contributory. There was no history suggestive of visual or hearing loss, seizures, bladder and bowel involvement or extrapyramidal symptoms. On examination, Head size was large for age with hyper pigmented nevi over right arm. There was delay involving language, motor and cognition. CNS examination revealed stance ataxia with generalized hypotonia. No obvious organomegaly was noted on abdominal examination. MRI done in August 2014 showed signal abnormality in dorsal brainstem, dentate nuclei, bilateral thalami and basal ganglia. Gyri appeared swollen with subcortical U fiber involvement. Central white matter was spared. MRS revealed elevated borderline elevation of NAA and lactate. CT did not reveal any obvious calcification in these areas. Based on these findings differential diagnosis of mitochondrial etiology and L2 hydroxyglutaric aciduria were considered. However, urine tests for routine organic acids were negative. Literature search revealed findings fitting into Canavan variant disease. Consequently, urine examination showed elevated N acetyl aspartate. The ASPA gene mutation was confirmed on genetic testing. Another case showed similar clinical presentation. However head size was normal in second case. Imaging findings were similar in nature. Genetic mutation confirmed the diagnosis. Recognition of the Canavan Variant is important, as most of the cases would be diagnosed as mitochondrial (Leigh’s/ LBSL) or L2 hydroxyglutaric aciduria initially. This pattern recognition lead to correct genetic testing and diagnosis.
IPR 2016 Conjoint Meeting & Exhibition
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