Torpedo Maculopathy Associated with NEXMIF Mutation

Tuğba Alarcon-Martinez; Ayesha Khan; Kenneth A Myers

doi:10.1159/000498835

Torpedo Maculopathy Associated with NEXMIF Mutation

Mol Syndromol. 2019 Jul;10(4):229-233. doi: 10.1159/000498835. Epub 2019 Mar 15.

Authors

Tuğba Alarcon-Martinez¹, Ayesha Khan^{2

3}, Kenneth A Myers^{1

3}

Affiliations

¹ Division of Child Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, McGill University, Montreal, QC, Canada.
² Department of Ophthalmology, Montreal Children's Hospital, McGill University Health Centre, McGill University, Montreal, QC, Canada.
³ Research Institute of the McGill University Health Centre, Montreal, QC, Canada.

Abstract

Mutations in the neurite extension and migration factor (NEXMIF) gene are associated with X-linked intellectual disability. Thus far, all males reported with NEXMIF 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 NEXMIF pathogenic variant (p.Glu375ArgfsX21) who has mild motor delay, language delay, autistic features, and strabismus. In addition to these commonly described findings of NEXMIF mutations, his fundus exam revealed a very rare ophthalmologic abnormality, torpedo maculopathy. This finding has not previously been reported with NEXMIF mutation; however, on literature review, 7/15 males with NEXMIF mutations had other ophthalmologic abnormalities. This patient expands the phenotypic spectrum for males with NEXMIF mutations and suggests that NEXMIF may play an important role in ocular development.

Keywords: Generalized epilepsy; NEXMIF; Torpedo maculopathy; X-linked intellectual disability.