A Normal EOG in Best Macular Dystrophy Associated to a Novel Novo de Novo Mutation in VMD2 Gene

Abstract

Purpose:: To describe a novel de novo mutation of VMD2 gene in an Italian family affected by Best macular dystrophy.

Methods:: All six family members underwent ophthalmologic examination including best-corrected visual acuity by Snellen visual charts, Ishihara color test, slit-lamp biomicroscopy, dilated fundus examination, fundus photography, scanning laser ophthalmoscopy, optical coherence tomography, electrophysiological tests, such as electroretinogram and electrooculogram. The genetic testing was performed by single strand conformation polymorphism analysis and direct sequencing of the VDM2 gene.

Results:: The sequence analysis of the VMD2 gene revealed a single Phe to Leu transition at nucleotide 305 in three members of our family, father and his two children, while no mutation was identified in the other two unaffected parents. In patients with mutation of VMD2 gene the ophthalmic examination disclosed a typical phenotype of Best macular dystrophy. The father showed a vitelliform cyst stage in both eye while his two childrens demostrated different macular lesion ranging from previtelliform to scrambled egg stage. The electro-oculography, showed a light rise reduced in the older patient and normal value (Arden ratio > 1.65) in the two childrens.

Conclusions:: The outcomes of this study underline the recurrence of de novo mutations in VMD2 gene and itâ€^TMs involvement in Best macular dystrophy even in patients showing a normal electro-oculogram. The occurence of a normal electro-oculography in patient with VMD2 mutation seems to be related to a specific genotype, thus confirming the relevance of molecular analysis in the diagnosis of the disease.

Keywords: retinal pigment epithelium • retinal development • retinoids/retinoid binding proteins