# Infantile Cataracts Associated with a Homozygous Missense MSMO1 Variant—Case Report and Literature Review

## TL;DR

A patient with infantile cataracts and developmental delays was found to have a rare genetic variant in the MSMO1 gene, which is linked to cholesterol synthesis and eye development.

## Contribution

This case expands the known clinical features of MSMO1 deficiency and its connection to infantile cataracts.

## Key findings

- A homozygous likely pathogenic variant in MSMO1 was identified in a patient with infantile cataracts and developmental delay.
- Impaired cholesterol synthesis due to MSMO1 deficiency is linked to early lens opacification and cataract formation.
- The case highlights the importance of cholesterol biosynthesis in early lens development.

## Abstract

Background and Clinical Significance: MSMO1, encoding a key enzyme in the cholesterol synthesis pathway, is associated with an autosomal recessive condition characterized by microcephaly, ocular abnormalities, growth delay, psoriasiform dermatitis, immune dysfunction, and intellectual disability. Case Presentation: This report describes a patient presenting with global developmental delay and bilateral infantile cataracts found to harbor a homozygous likely pathogenic MSMO1 variant and reviews the literature on MSMO1 deficiency and its association with infantile cataracts. Conclusions: The mechanism of early lens opacification is thought to result from impaired cholesterol synthesis, altering the lipid composition of the lens membrane and leading to early cataract formation. This case expands our understanding of MSMO1 deficiency and highlights the critical role of cholesterol biosynthesis in early lens development.