Torpedo Maculopathy Associated with NEXMIF Mutation

Abstract

Mutations in the neurite extension and migration factor (<i>NEXMIF</i>) gene are associated with X-linked intellectual disability. Thus far, all males reported with <i>NEXMIF</i> mutations have mild to profound intellectual disability with varying combinations of autistic features, poor or absent speech, epilepsy, facial dysmorphism, and strabismus. Affected females tend to have milder intellectual disability but severe, drug-resistant epilepsy. Here, we present a 32-month-old boy with a novel de novo frameshift <i>NEXMIF</i> pathogenic variant (p.Glu375ArgfsX21) who has mild motor delay, language delay, autistic features, and strabismus. In addition to these commonly described findings of <i>NEXMIF</i> mutations, his fundus exam revealed a very rare ophthalmologic abnormality, torpedo maculopathy. This finding has not previously been reported with <i>NEXMIF</i> mutation; however, on literature review, 7/15 males with <i>NEXMIF</i> mutations had other ophthalmologic abnormalities. This patient expands the phenotypic spectrum for males with <i>NEXMIF</i> mutations and suggests that NEXMIF may play an important role in ocular development.