A Chinese Family with X-Linked Female-Limited High Myopia Caused by an ARR3 Variant.

BACKGROUND

X-linked female-limited high myopia (MYP26, OMIM:301010) is a rare Mendelian subtype of early-onset high myopia (eoHM), with females having progressive myopic refractive error (≥-6 D) and males as asymptomatic carriers. Pathogenic variants in ARR3 (OMIM:301770) have been linked to eoHM, but the spectrum of ARR3 variants in Chinese populations remains incompletely defined.

OBJECTIVE

To identify the causative variant in a Chinese eoHM family and expand ARR3 variant spectrum for MYP26.

METHODS

We conducted clinical and genetic analyses of a Chinese family with eoHM. The proband underwent clinical examinations and whole-exome sequencing (WES). Sanger sequencing validated variants in affected family members, and bioinformatics tools evaluated variant pathogenicity.

RESULTS

WES identified an ARR3 c.214C>T (p.R72X) stop-gain variant, co-segregating with the disease phenotype and predicted to truncate cone arrestin, disrupting phototransduction. A female carrier showing incomplete penetrance (I-1) was identified, which highlights the unrecognized complexity of the pathogenic mechanism underlying MYP26. This variant was first reported in the Chinese population.

CONCLUSIONS

Our study expands the ARR3 variant spectrum associated with eoHM, highlighting the role of ARR3 c.214C>T (p.R72X), first reported in Chinese populations. The finding of incomplete penetrance underscores the complexity of X-linked female-limited inheritance and provides a reference for genetic counseling of related families.