Pelizaeus-Merzbacher disease-like disorder in an Indian girl with a missense variant in GJC2 gene

Abstract

Pelizaeus-Merzbacher-like disease 1 (PMLD1) is a slowly progressive leukodystrophy that typically presents during the neonatal or early infantile period with nystagmus, commonly associated with hypotonia, delayed acquisition of motor milestones, speech delay and dysarthria. We present a 7-year-old female born to a nonconsanguineous marriage with developmental delay. On examination, she had 22 teeth, and nystagmus with pseudophakia. Neurological examination showed spasticity with increased deep tendon reflexes. On investigation, MRI of the brain done at 3 years showed hypomyelination. Targeted exome sequencing revealed a homozygous non-synonymous variation c.138C>G in exon 2 of the GJC2 gene. Sanger sequencing was done which showed the presence of a variant in the heterozygous state in both parents. PMLD1 should be suspected in any child presenting with diffuse hypomyelination with abnormal eye movements, especially in a girl child with PelizaeusMerzbacher disease phenotype with hypomyelination in the pons.