Postaxial polydactyly is characterised by fifth digit duplications in hands and/or feet. Two phenotypic varieties have been described. In type A, the extra digit is well formed and articulates with the fifth or an extra metacarpal. A rudimentary extra fifth digit characterises type B. Mutations in the GLI3 gene are associated with postaxial polydactyly in some families and a second locus has been identified on chromosome 13 but the majority of cases remain unexplained. We report here a third locus for postaxial polydactyly on chromosome 19p13.1-13.2 in a large Chinese kindred with a combination of type A and B. Two-point linkage analysis showed the highest LOD score (Zmax=5.85 at χ=0 cM) at marker D19S221. Recombination events with markers D19S1165 and D19S929 define the critical region for this postaxial polydactyly locus to a region of 4.3 cM on the genetic map.

Chromosome 19p13.1-13.2, Linkage, Postaxial polydactyly,
European Journal of Human Genetics

Zhao, H. (Hongshan), Tian, Y, Breedveld, G.J, Huang, S, Zou, Y, Chai, J.Y.J. (Jue Y. Jinghua), … Heutink, P. (2002). Postaxial polydactyly type A/B (PAP-A/B) is linked to chromosome 19p13.1-13.2 in a chinese kindred. European Journal of Human Genetics, 10(3), 162–166. doi:10.1038/sj.ejhg.5200790