LAUSR

Autosomal recessive bestrophinopathy is a rare disease caused by mutations of the BEST1 gene. Clinical findings of this disease include solitary or multifocal vitelliform lesions, subretinal and intraretinal fluids, RPE irregularities, hyperopia, and shallow anterior chamber (1). Retinal vein occlusion (RVO) may occur in patients older than 50 years old with vascular risk factors. In cases of RVO in young adults and children, searching for systemic predisposing conditions, such as thrombophilia is required (2). The MTHFR gene encodes methylenetetrahydrofolate reductase. This enzyme is necessary for the conversion of homocysteine to methionine. MTHFR mutation can increase plasma homocysteine levels and cause significant morbidities (3). Two common MTHFR mutations are 677C→T and 1298A→C and both of these can reduce enzyme activity. Both types are associated with venous thromboembolism (3). The 1298A→C polymorphism may not increase plasma homocysteine levels but this polymorphism is associated with many disorders (4). A1298C and C677T mutations in heterozygous and homozygous forms can increase the risk of thromboembolism without significant correlation with homocysteine levels (5). Heterozygote 1298A→C mutation (single variant change) has also been reported in the case with bilateral lens subluxation and vascular occlusion (6). In this report, we describe a case of branch retinal vein occlusion (BRVO) due to heterozygote MTHFR 1298A→C mutation in a child with autosomal recessive bestrophinopathy who also had a history of bilateral lensectomy due to inferior lens dislocation 6 years before this. This is the first reported case of autosomal recessive bestrophinopathy together with MTHFR mutation.