Introduction: Hypomyelinating leukodystrophies are phenotypically and genetically heterogenous disorders with pathogenic variants in 15 genes. Leukodystrophy, hypomyelinating, 5 (HLD5, MIM# 610532), also known as hypomyelination with congenital cataract, presents with congenital cataract and infantile onset progressive neuroregression, spasticity, dysarthria, hypomyelination with or without peripheral neuropathy.

Methods: Clinical evaluation followed by mutation analysis by exome sequencing. Validation of the sequence variant in index patient and his parents by Sanger sequencing.

Case Report: We ascertained a five-year-old boy, third born to a consanguineously married couple. His development was normal till 10 months of age. Thereafter, neuroregression was noted. He had history of myoclonic and generalized tonic clonic seizures since 2 years and 6 months of age. On examination, spasticity and nystagmus were noted. Ophthalmological examination demonstrated bilateral zonular cataract. The magnetic resonance images of brain revealed hypomyelination.

Results: A novel missense variant, c.179T>C p.(Leu60Pro) in exon 4 of FAM126A was observed in homozygous state in the proband and in heterozygous state in the parents.

Discussion: Homozygous or compound heterozygous loss of function and missense variants in FAM126A are known to cause HLD5. We hereby discuss clinical presentation of a child with the said condition and report a novel missense variant in FAM126A.

Acknowledgements: We thank the patient and his family for participating in the study. We also thank the Department of Health Research, Ministry of health and family welfare, Government of India for funding the project entitled “Clinical and molecular characterization of leukodystrophies in Indian children” (V.25011/379/2015-GIA/HR) to Dr Anju Shukla.