The USH1C 216G-->A mutation and the 9-repeat VNTR(t,t) allele are in complete linkage disequilibrium in the Acadian population

Hum Genet. 2002 Jan;110(1):95-7. doi: 10.1007/s00439-001-0653-7. Epub 2001 Dec 6.

Abstract

Recently, mutations in USH1C were shown to be associated with Usher syndrome type IC, and a mutation (216G-->A) in exon 3 was identified in an Acadian family. In addition, a 45-bp variable number of tandem repeat (VNTR) polymorphism was found in intron 5 of USH1C. Polymerase chain reaction amplification of the VNTR region and restriction enzyme analysis of exon 3 of USH1C showed that, of 44 Acadian patients, 43 were homozygous for both the 216G-->A mutation and nine repeats of the VNTR, with a "t" nucleotide replacing a "g" nucleotide at the 8th position of both the eighth and ninth copies of the repeat, viz., 9VNTR(t,t). The remaining Acadian patient was reported to be a compound heterozygote for 216G-->A/9VNTR(t,t) and 238-239insC, a USH1C mutation that has been found in other populations. These data demonstrate that the 9VNTR(t,t) allele is in complete linkage disequilibrium with the 216G-->A mutation in the Acadian population. Among 82 Acadian controls, one was heterozygous for 216G-->A/9VNTR(t,t). The 238-239insC mutation was not found in Acadian controls. Analysis of 340 non-Acadian normal samples showed the presence of a 9-repeat VNTR allele in one Hispanic sample. This individual had neither the 216G-->A mutation nor the Acadian VNTR(t,t) structure. These results suggest that the 216G-->A mutation and the 9VNTR(t,t) allele are restricted to the Acadians and are in complete linkage disequilibrium.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Base Sequence
  • Carrier Proteins / genetics*
  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • Ethnicity / genetics
  • Hearing Disorders / genetics
  • Humans
  • Linkage Disequilibrium*
  • Louisiana
  • Minisatellite Repeats*
  • Polymorphism, Single Nucleotide*
  • Reference Values
  • Retinal Degeneration / genetics
  • Syndrome

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • USH1C protein, human