The 2588G-->C mutation in the ABCR gene is a mild frequent founder mutation in the Western European population and allows the classification of ABCR mutations in patients with Stargardt disease

Am J Hum Genet. 1999 Apr;64(4):1024-35. doi: 10.1086/302323.

Abstract

In 40 western European patients with Stargardt disease (STGD), we found 19 novel mutations in the retina-specific ATP-binding cassette transporter (ABCR) gene, illustrating STGD's high allelic heterogeneity. One mutation, 2588G-->C, identified in 15 (37.5%) patients, shows linkage disequilibrium with a rare polymorphism (2828G-->A) in exon 19, suggesting a founder effect. The guanine at position 2588 is part of the 3' splice site of exon 17. Analysis of the lymphoblastoid cell mRNA of two STGD patients with the 2588G-->C mutation shows that the resulting mutant ABCR proteins either lack Gly863 or contain the missense mutation Gly863Ala. We hypothesize that the 2588G-->C alteration is a mild mutation that causes STGD only in combination with a severe ABCR mutation. This is supported in that the accompanying ABCR mutations in at least five of eight STGD patients are null (severe) and that a combination of two mild mutations has not been observed among 68 STGD patients. The 2588G-->C mutation is present in 1 of every 35 western Europeans, a rate higher than that of the most frequent severe autosomal recessive mutation, the cystic fibrosis conductance regulator gene mutation DeltaPhe508. Given an STGD incidence of 1/10,000, homozygosity for the 2588G-->C mutation or compound heterozygosity for this and other mild ABCR mutations probably does not result in an STGD phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / genetics*
  • Amino Acid Sequence
  • Base Sequence
  • Cells, Cultured
  • Corneal Dystrophies, Hereditary / epidemiology
  • Corneal Dystrophies, Hereditary / genetics*
  • Corneal Dystrophies, Hereditary / pathology
  • DNA Mutational Analysis
  • Europe / epidemiology
  • Exons / genetics
  • Founder Effect*
  • Gene Frequency
  • Genetic Predisposition to Disease / genetics
  • Genotype
  • Humans
  • Incidence
  • Linkage Disequilibrium / genetics
  • Phenotype
  • Point Mutation / genetics*
  • Polymorphism, Genetic / genetics
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics
  • Retinitis Pigmentosa / epidemiology
  • Retinitis Pigmentosa / genetics

Substances

  • ABCA4 protein, human
  • ATP-Binding Cassette Transporters
  • RNA, Messenger