Mutations in the hBest1 (VMD2) gene are linked to various kinds of macular degeneration, including Best vitelliform macular dystrophy (BVMD) and adult-onset vitelliform macular dystrophy (AVMD).
Mutations in the BEST1 gene cause the retinal dystrophies vitelliform macular dystrophy, autosomal-dominant vitreochoroidopathy, and autosomal-recessive bestrophinopathy.
Six subjects were identified with BEST1 mutations (three male, three female; aged 8 to 30 years) without clinically detectable (subclinical) Best VMD (absence of both symptoms and funduscopic lesions).
Best macular dystrophy (BMD), also known as vitelliform macular dystrophy (VMD2; OMIM 153700), is an autosomal dominant form of macular degeneration characterized by an abnormal accumulation of lipofuscin within and beneath the retinal pigment epithelium cells.
To report a child with early-onset autosomal recessive Best vitelliform macular dystrophy and compound heterozygous BEST1 mutations, the management of a choroidal neovascular membrane with intravitreal bevacizumab in the proband, the benefits of amblyopia therapy in the fellow eye, and the findings in the parents, carriers of heterozygous BEST1 mutations.
However, because variable expressivity of VMD2 was observed in a family with the Q293H mutation, it is also clear that a disease-linked mutation in VMD2 is not sufficient to produce BVMD.
Ten of these 11 patients (91%) with maculopathy had a mutation in the VMD2 gene, of whom 8 were clinically diagnosed as having Best disease and 2 were diagnosed as having possible Best maculopathy.
Substitution of the RPE-specific promoter from the vitelliform macular dystrophy (VMD2) gene for the CMV promoter resulted in prolonged (at least 1 year) expression of LacZ that was restricted to RPE cells, albeit reduced 6- to 10-fold compared with the CMV promoter.
Here, we characterized six Best vitelliform macular dystrophy (BVMD)-associated BEST1 dominant mutations by documenting the patients' phenotypes, examining the subcellular localization of endogenous BEST1 and surface Ca<sup>2+</sup>-dependent Cl<sup>-</sup> currents in patient-derived RPEs, and analyzing the functional influences of these mutations on BEST1 in HEK293 cells.
Best macular dystrophy (BMD) is an autosomal dominant retinopathy caused by mutations in the VMD2 gene that encodes a chloride channel in the basolateral membrane of the retinal pigment epithelium (RPE).
Vitelliform macular dystrophy (VMD2, Best disease, MIM153700) is an early onset, autosomal, dominant macular degeneration characterized by the deposition of lipofuscin-like material within and below the retinal pigment epithelium (RPE); it is associated with degeneration of the RPE and overlying photoreceptors.
The high prevalence of novel variants and the frequent report of a specific variant (p.Arg25Trp) that has rarely been described in other ethnic groups suggests a distribution of BEST1 variants peculiar to Italian VMD patients.
Mutations in the VMD2 gene are associated with juvenile-onset vitelliform macular dystrophy (Best disease) and adult vitelliform macular dystrophy but not age-related macular degeneration.
Two previously unreported disease-associated variants in the BEST1 gene (p.Gly15Arg and p.Arg105Gly) were found in Slovenian patients with Best disease.
Sanger sequencing of all exons of the BEST1 gene in both families identified two new mutations: a missense mutation c.C91A [p.L31 M] at the N-terminal transmembrane domain within the ARB family and a nonsense mutation C1550G (p.S517X) in the C-terminal domain segregating in the BVMD family.