Abstract
Purpose :
Mutations in BEST1 cause several phenotypes including autosomal dominant (AD) Best vitelliform macular dystrophy type 2 (BVMD), AD vitreoretinochoroidopathy (ADVIRC), and retinitis pigmentosa-50 (RP50). These retinopathies are characterized by vitelliform dystrophy for which ophthalmologists like to describe 5 stages, going from pre-vitelliform to the atrophic final stage. A rare subtype of bestrophinopathy exists with biallelic mutations in BEST1. Its frequency is estimated to be 1/1’000’000 individuals.
Methods :
We report 5 cases and establish a phenotype-genotype correlation. All patients were referred because of reduced best-corrected visual acuity, ranging from 0.1/10 to 3/10. All patients showed vitelliform lesions present at the macula, sometimes extending into the midperiphery and along the vessels and optic disc. Onset of the disease varied from the age of three to 25 years. Electrooculogram (EOG) revealed reduction in the EOG light rise in all patients.
Results :
Molecular analysis revealed the previously reported mutations p.[R141H];[A195V], p.[E35K];[E35K], and p.[R202W]; [R202W]. Two families showed novel mutations: p.[Q220*];[Q220*] and p.[L31M];[L31M]. All mutations were heterozygous in the parents. In one family, heterozygous children showed various reductions in the EOG light rise and autofluorescent deposits.
Conclusions :
ARB, also rare, can be recognized by its phenotype and should be validated by molecular analysis. Phenotype-genotype correlations are hard to establish and will have to wait for more cases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.