BEST1 VARIANT ASSOCIATED WITH AN ATYPICAL MACULAR AND PERIPHERAL RETINAL PHENOTYPE.

Purpose: Best vitelliform macular dystrophy is an inherited macular dystrophy associated with over 250 pathogenic variants of the Bestrophin-1 ( BEST1 ) gene. Although several types of lesions of best vitelliform macular dystrophy are well-described, reports of phenotypic variations associated with rare genetic variants are limited.

Methods: This was a retrospective case series performed in 2021 at a tertiary eye care center.

Patients: Three members of one family referred to a tertiary eye care clinic for evaluation of their autosomal dominant macular dystrophy.

Results: Study subjects presented with atypical findings of peripheral schisis-like lesions and atrophy with abnormal electroretinogram in addition to typical macular lesions found in best vitelliform macular dystrophy. Genetic analyses identified a heterozygous BEST1 c.227T>A, p.(Ile76Asn) pathogenic variant in all three subjects.

Conclusion: This study represents the first report of the phenotype associated with the c.227T>A, p.(Ile76Asn) BEST1 variant, which-while mentioned twice in the literature-has not been previously described. The phenotype is unique, comprising features of typical best vitelliform macular dystrophy with electroretinogram and peripheral findings, suggestive of a panretinal dysfunction.