Functional and clinical data of Best vitelliform macular dystrophy patients with mutations in the BEST1 gene.

PURPOSE: To analyze functional and clinical data of Best vitelliform macular dystrophy (VMD) patients with mutations in the BEST1 gene. METHODS: Best VMD patients with BEST1 mutations were evaluated prospectively regarding age, age of onset, best-corrected visual acuity (BCVA), fundus autofluorescence, fluorescein angiography, optical coherence tomography, and electro-oculography. Mutations in BEST1 were established by direct sequencing. RESULTS: Forty-six eyes of 23 patients (10 male, 13 female) were included in the study. We identified nine different BEST1 mutations (3/9 novel), in ten unrelated families. The age of patients ranged between 3 and 75 years; age of onset varied between 2 and 67 years. BCVA ranged between 20/20 and 20/200. On the basis of fundus biomicroscopy with direct illumination, using one widely accepted classification, the macular lesions could be counted as follows: 1. no lesion (normal fovea): eight eyes, five patients carrying a mutation on the BEST1 gene; 2. previtelliform lesions: six eyes, three affected patients; 3. vitelliform lesions: four eyes, two affected patients; 4. pseudohypopyon: three eyes, three affected patients; 5. vitelliruptive lesions (scrambled egg aspect with dispersion of the vitelliform material without sign of atrophy or fibrosis): ten eyes, six affected patients; 6. atrophic lesions (atrophy with or without residual dispersed material): seven eyes, five patients; 7. fibrotic lesions: eight eyes, five patients. Two patients presented unilateral Best VMD. Both eyes of two patients presented multifocal Best VMD features on fundus examination. Six eyes of four patients have been treated for choroidal neovascularization by thermic photocoagulation [one eye], photodynamic therapy [three eyes], and intravitreal ranibizumab injection [two eyes]. Comparison of interfamilial and intrafamilial clinical data between patients did not reveal differences in age, BCVA, and stage of the disease as evaluated by fundus autofluorescence, fluorescein angiography, and optical coherence tomography (p>0.05). Mean BCVA impairment showed a statistically significant correlation to a more advanced stage of the disease (p<0.001). CONCLUSIONS: BEST1 mutations were not correlated with the severity of the functional and clinical data in the Best VMD patients examined.

Identification of GLA gene deletions in Fabry patients by Multiplex Ligation-dependent Probe Amplification (MLPA).

Fabry disease is an under-recognized X-linked lysosomal disorder, due to alpha-galactosidase A deficiency. Most of the mutations in the GLA gene are detectable using genomic sequencing analysis. However, deletions of one or more exons or deletion encompassing the entire gene are undetectable, especially in heterozygous females. The Multiplex Ligation-dependent Probe Amplification (MLPA) is an efficient tool for discovering these rearrangements. In this study two novel different deletions were detected using MLPA assay on two Fabry patients, both resulted mutation negative by sequencing analysis. These data suggest that this screening should be systematically included in genetic testing surveys of patients with Fabry disease.

The spectrum of subclinical Best vitelliform macular dystrophy in subjects with mutations in BEST1 gene.

PURPOSE: To describe the morphologic and functional characteristics of subclinical Best vitelliform macular dystrophy (VMD) in subjects with mutation in the BEST1 gene. METHODS: Best-corrected visual acuity (BCVA), funduscopic appearance, fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT), and electro-oculography (EOG) were assessed in 23 consecutive subjects from nine unrelated families with known mutations in the BEST1 gene (eight distinct BEST1 mutations). RESULTS: 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). All six subjects showed 20/20 BCVA and normal FAF findings. In these 6 of 26 subjects from five different families, we found five distinct mutations in the BEST1 gene. In three (six eyes) out of these six subjects with BEST1 gene mutations (two families: p.G15D; p.A243V), SD-OCT showed overall normal findings. In the other three subjects (six eyes) with BEST1 gene mutations (three families: p.V9A; p.R92C; p.I230T), we found, on SD-OCT, a thicker and more reflective appearance of the layer between the retinal pigment epithelium and the interface of inner segments and outer segments of the photoreceptor (the Verhoeff's membrane). EOG showed a reduced light-peak:dark-trough ratio in 5 of 12 eyes. Changes on SD-OCT were present in the absence of EOG abnormalities (two of six eyes), and vice versa (one of six eyes). CONCLUSIONS: Subclinical Best VMD (absence of both symptoms and funduscopic lesions) in subjects with BEST1 mutation may vary from the absence of any morphologic and functional abnormalities to the presence of specific SD-OCT and EOG changes.