Open AccessBloom syndrome: an analysis of consanguineous families assigns the locus mutated to chromosome band 15q26.1.
Author(s) -
James German,
Anne Marie Roe,
M. Leppert,
Nathan A. Ellis
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.14.6669
Subject(s) - locus (genetics) , genetics , consanguinity , biology , identity by descent , disease gene identification , genetic linkage , gene , allele , haplotype , phenotype , exome sequencing
By the principle of identity by descent, parental consanguinity in individuals with rare recessively transmitted disorders dictates homozygosity not just at the mutated disease-associated locus but also at sequences that flank that locus closely. In 25 of 26 individuals with Bloom syndrome examined whose parents were related, a polymorphic tetranucleotide repeat in an intron of the protooncogene FES was homozygous, far more often than expected (P < 0.0001 by chi 2). Therefore, BLM, the gene that when mutated gives rise to Bloom syndrome, is tightly linked to FES, a gene whose chromosome position is known to be 15q26.1. This successful approach to the assignment of the Bloom syndrome locus to one short segment of the human genome simultaneously (i) demonstrates the power of homozygosity mapping and (ii) becomes the first step in a "reverse" genetics definition of the primary defect in Bloom syndrome.