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Am J Hum Genet. 2008 Jan;82(1):19-31. doi: 10.1016/j.ajhg.2007.08.004.

Biallelic mutation of BEST1 causes a distinct retinopathy in humans.

Author information

1
Academic Unit of Medical Genetics and Regional Genetics Service, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK.

Abstract

We describe a distinct retinal disorder, autosomal-recessive bestrophinopathy (ARB), that is consequent upon biallelic mutation in BEST1 and is associated with central visual loss, a characteristic retinopathy, an absent electro-oculogram light rise, and a reduced electroretinogram. Heterozygous mutations in BEST1 have previously been found to cause the two dominantly inherited disorders, Best macular dystrophy and autosomal-dominant vitreoretinochoroidopathy. The transmembrane protein bestrophin-1, encoded by BEST1, is located at the basolateral membrane of the retinal pigment epithelium in which it probably functions as a Cl(-) channel. We sequenced BEST1 in five families, identifying DNA variants in each of ten alleles. These encoded six different missense variants and one nonsense variant. The alleles segregated appropriately for a recessive disorder in each family. No clinical or electrophysiological abnormalities were identified in any heterozygotes. We conducted whole-cell patch-clamping of HEK293 cells transfected with bestrophin-1 to measure the Cl(-) current. Two ARB missense isoforms severely reduced channel activity. However, unlike two other alleles previously associated with Best disease, cotransfection with wild-type bestrophin-1 did not impair the formation of active wild-type bestrophin-1 channels, consistent with the recessive nature of the condition. We propose that ARB is the null phenotype of bestrophin-1 in humans.

PMID:
18179881
PMCID:
PMC2253971
DOI:
10.1016/j.ajhg.2007.08.004
[Indexed for MEDLINE]
Free PMC Article

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