Novel LOXL3-associated stickler syndrome-like phenotype: a case report.

Abstract

Purpose: To report the case of a young boy with early onset high myopia (eoHM), foveal hypoplasia and skeletal dysplasia due to a homozygous LOXL3 pathogenic variant. Atypically, this was from a paternal uniparental isodisomy (UPiD) of chromosome 2.

Clinical case: Four-year-old boy with several months history of holding items close to his face was found to have reduced visual acuity 6/30 in both eyes, bilateral vitreous syneresis, foveal hypoplasia and bilateral high myopia (-8.50D). A skeletal survey showed spondylo-epi-metaphyseal dysplasia. Whole-exome sequencing (WES) revealed a homozygous LOXL3 variant c.1448_1449del, p.(Thr483Argfs*13), inherited through paternal UPiD of chromosome 2.

Conclusion: To our knowledge, this is the first reported case of LOXL3-associated eoHM, foveal hypoplasia and mild skeletal dysplasia due to the rare phenomenon of paternal UPiD of chromosome 2. This case further delineates the phenotype associated with LOXL3 pathogenic variants and supports truncating LOXL3 pathogenic variants being associated with a phenotypic spectrum; from isolated eoHM through to a Stickler syndrome-like phenotype.