LINKAGE OF PREAXIAL POLYDACTYLY TYPE-2 TO 7Q36

We have characterized a 6-generation North American Caucasian kindred segregating one form of preaxial polydactyly type 2 (PPD-2). We demons trate linkage to the 7q36 region and describe a submicroscopic telomer ic chromosomal deletion in phase with the PPD-2 phenotype. Recently, s everal kindreds segregating triphalangeal thumb (TPT) with and without associated hand anomalies (syndactyly and/or postaxial polydactyly) h ave also been linked to the subtelomeric region of chromosome 7q [Heut ink et al., 1994: Nat Genet 6:287-291; Tsukurov et al., 1994: Nat Gene t 6:282-286]. We demonstrate by haplotype analysis that our North Amer ican pedigree represents a PPD allele that is independent of the found er PPD allele present in the previously described kindreds. (C) 1995 W iley-Liss, Inc.