Best's macular dystrophy in Australia: phenotypic profile and identification of novel BEST1 mutations

(1) To evaluate the spectrum of BEST1 mutations within Australian Best Disease or vitelliform macular dystrophy (VMD) pedigrees, including any novel mutations; (2) to analyse the range of clinical presentations of this cohort; (3) to determine any possible genotype-phenotype correlations and (4) to compare clinical data of patients with phenotypic VMD, both with and without a BEST1 mutation.

Patients with suspected VMD were referred to clinical centres for ophthalmological assessment and genetic screening. When a mutation was identified in a proband, further family members were invited for clinical and genetic screening.

We identified 42 patients with one of 13 BEST1 mutations. Seven mutations were novel. There were a further 14 probands in whom a BEST1 mutation was not identified. Median visual acuity in both VMD (mutation positive) and clinical VMD (no BEST1 mutation identified) groups reached driving standards (6/12 or better).

We did not identify any firm genotype-phenotype correlations in our Australian VMD pedigrees, in which there was a spectrum of BEST1 mutations and marked variation in clinical presentation. Genetic screening remains the gold standard for VMD diagnosis. Patients should be counselled that visual acuity might remain at or above driving standards in at least one eye even in the presence of a BEST1 mutation.