A locus for brachydactyly type A-1 maps to chromosome 2q35-q36

Brachydactyly type A-1 (BDA1) was, in 1903, the first recorded example of a human anomaly with Mendelian autosomal dominant inheritance. Two large fam ilies, the affected members of which were radiographed, were recruited in t he study we describe here. Two-point linkage analysis for pedigree 1 (maxim um LOD score [Z(max)] 6.59 at recombination fraction [theta] 0.00) and for pedigree 2 (Z(max) = 5.53 at theta = 0.00) mapped the locus for BDAI in the two families to chromosome 2q. Haplotype analysis of pedigree 1 confined t he locus for family 1 within an interval of <8.1 cM flanked by markers D2S2 248 and D2S360, which was mapped to chromosome 2q35-q36 on the cytogenetic map. Haplotype analysis of pedigree 2 confined the locus for family 2 withi n an interval of <28.8 cM. flanked by markers GATA30E06 and D2S427, which w as localized to chromosome 2q35-q37. The two families had no identical hapl otype within the defined region, which suggests that the two families mere not related.