Predicting the age of the mutation for Usher syndrome type I in the Acadian population
- Louisiana State Univ., NO (United States); and others
The locus for Usher syndrome type I (USH1C) in the Acadian population is in the p15.1-p14 region of chromosome 11. This recessive disease is characterized by sensorineural hearing impairment, vestibular dysfunction, and pigmentary retinopathy. Three separate loci have been localized for Usher syndrome type I. All Acadian, but no non-Acadian, families show linkage to the 11p locus, suggesting a founder effect in the Acadian population. Linkage and haplotype analyses of eight markers spanning 10 centiMorgans demonstrate that USH1C lies between D11S1397 and D11S1310. Based on analyses of Usher and CEPH families the most likely linkage map for the eight markers is: D11S569-(.02)-D11S861-(.01)-D11S419-(.01)-D11S1397-(.004)-D11S921-(.007)-D11S1310-(.01)-D11S899-(.04)-D11S928. Evidence of linkage disequilibrium with USH1C was found for all markers, indicating a recent origin of a unique mutation. Parental haplotypes were separated into those with the disease allele and those with the normal allele at the USH1C locus. Of the 54 chromosomes with the disease allele, 17 had an identical haplotype for the eight markers. All but one of the haplotypes on the remaining 37 chromosomes could be explained by a few recombination events, suggesting that a single mutation is responsible for nearly all cases of Usher syndrome type I in the Acadian population. The same alleles were found at D11S921 and D11S1310 on 50 of the 54 chromosomes with the disease allele and on only 5 of the 50 chromosomes with the normal allele. Analysis of recombination and linkage disequilibrium between USH1C and each of the markers suggests that the age of the mutation is approximately 15 generations, which corresponds with the time that the Acadians arrived in the Canadian territory of Acadia. The analysis indicates that this mutation was already established in the Acadians who made their way to Louisiana after 1755.
- OSTI ID:
- 133923
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-0657
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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