Metachromatic Leukodystrophy with PSAP Gene Mutation

Metachromatic leukodystrophy is a rare neurodegenerative lysosomal disease caused by deficiency of enzymes arylsulfatase A results in accumulation of cerebroside sulfatide in white matter of central and peripheral nervous system. Mutation in gene ARSA and, in rare cases, due to variations in the PSAP gene causes saposin-B deficiency and is inherited in an autosomal recessive pattern. There are three types of MLD based on the age symptoms appear: late-infantile MLD, juvenile MLD, and adult MLD, they affect both intellectual and motor function. Symptoms vary by type but can include difficulty talking and walking, seizures, personality changes, and behaviour and personality changes. Here we report a case of late infantile onset metachromatic leukodystrophy with normal arylsulfatase A activity, mutations in the PSAP gene, presented with regression of milestone and myoclonic seizures and diagnosis of MLD suspected on the basis of peculiar clinical history and confirmed on the basis of MRI and clinical exome studies.