Asparagine Synthetase deficiency-report of a novel mutation and review of literature.

Asparagine synthetase deficiency is a rare inborn error of metabolism caused by a defect in ASNS, a gene encoding asparagine synthetase. It manifests with a severe neurological phenotype manifesting as severe developmental delay, congenital microcephaly, spasticity and refractory seizures. To date, nineteen patients from twelve unrelated families have been identified. Majority of the mutations are missense and nonsense mutations in homozygous or compound heterozygous state. We add another case from India which harbored a novel homozygous missense variation in exon 11 and compare the current case with previously reported cases.