Assembly of a high-resolution map of the Acadian Usher syndrome region and localization of the nuclear EF-hand acidic gene

Usher syndrome type 1C (USH1C) occurs in a small population of Acadian descendants from southwestern Louisiana. Linkage and linkage disequilibrium analyses localize USH1C to chromosome 11p between markers D11S1397 and D11S1888, an interval of less than 680 kb. Here, we refine the USH1C linkage to a region less than 400 kb, between genetic markers D11S1397 and D11S1890. Using 17 genetic markers from this interval, we have isolated a contiguous set of 60 bacterial artificial chromosomes (BACs) that span the USH1C critical region. Exon trapping of BAC clones from this region resulted in the recovery of an exon of the nuclear EF-hand acidic (NEFA) gene. However, DNA sequence analysis of the NEFA cDNA from lymphocytes of affected individuals provided no evidence of mutation, making structural mutations in the NEFA protein unlikely as the cellular cause of Acadian Usher syndrome. Copyright (C) 1998 Elsevier Science B.V

Federal regulations and the future of research in human and medical genetics

Recent events in genetics research have generated questions about the efficacy of federal regulations that govern the conduct of biomedical research, particularly genetics research. The regulatory definitions of "human subject" and "private information" that have governed the conduct of research for two decades are presently under scrutiny because of ambiguities created by the methods of family studies in human and medical genetics. Geneticists customarily collect family history information for the purposes of tracking and characterizing genes in large families. Amassing family history information usually entails asking human subjects about the health status of collateral relatives. Whether these relatives should be regarded as human subjects for the purposes of giving informed consent is the issue that has triggered wide debate and an exhaustive re-examination of federal regulations and guidelines. The purpose of this article is threefold. First, a review of the development of current federal regulations provides a foundation and a point of departure for resolving current issues in genetics research. Second, a review of customary practices in genetics research furthers thought regarding regulations or guidelines to address specific issues in genetics. Third, it asserts that any new regulations or guidelines must provide appropriate protections for human subjects and their families while simultaneously supporting appropriate activities in genetics research

The USH1C 216G--\u3eA mutation and the 9-repeat VNTR(t,t) allele are in complete linkage disequilibrium in the Acadian population

Recently, mutations in USH1C were shown to be associated with Usher syndrome type IC, and a mutation (216G--\u3eA) 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--\u3eA 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--\u3eA/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--\u3eA mutation in the Acadian population. Among 82 Acadian controls, one was heterozygous for 216G--\u3eA/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--\u3eA mutation nor the Acadian VNTR(t,t) structure. These results suggest that the 216G--\u3eA mutation and the 9VNTR(t,t) allele are restricted to the Acadians and are in complete linkage disequilibrium