A physical and transcriptional map of the preaxial polydactyly locus on chromosome 7q36

Preaxial polydactyly is a congenital hand malformation that includes duplic ated thumbs, various forms of triphalangeal thumbs, and duplications of the index finger, A locus for preaxial polydactyly has been mapped to a region of 1.9 cM on chromosome 7q36 between polymorphic markers D7S550 and D7S242 3. We constructed a detailed physical map of the preaxial polydactyly candi date region. With a combination of methods we identified and positioned 11 transcripts within this map. By recombination analysis on families with pre axial polydactyly, using newly developed polymorphic markers, we were able to reduce the candidate region to approximately 450 kb. The homeobox gene H LXB9, a putative receptor C70rf2, and two transcripts of unknown function, C70rf3 and C70rf4, map in the refined candidate region and have been subjec ted to mutation analysis in individuals with preaxial polydactyly. (C) 1999 Academic Press.