Variant phenotype of best vitelliform macular dystrophy associated with compound heterozygous mutations in VMD2

Purpose: To characterize the phenotype of members of a Swedish family with Best macular dystrophy and two distinct mutations in VMD2. Methods: Venous blood samples were obtained from six family members and screened for mutations in VMD2. Six individuals were examined clinically, four of whom were further investigated with full-field electroretinography (ERG), electro-oculography (EOG), multifocal electroretinography (mfERG), and optical coherence tomography (OCT). Results: The VMD2 mutations resulting in Arg141His and Tyr29stop were identified in family members. Two individuals harbored both mutations, one mutation in each VMD2 allele. These two family members had an abnormal EOG and their full-field ERG demonstrated widespread degeneration with a prolonged implicit time in the cone 30-Hz flicker ERG. MfERG verified reduction of the central retinal function and OCT demonstrated intraretinal fluid, swelling, and thickening of the outer retina-RPE-choroid complex (ORCC). Conclusion: A previously undescribed severe form of Best macular dystrophy is associated with compound heterozygous mutations in VMD2.