Congenital vertical talus (CVT) is a primary dislocation of the talonavicular joint that often occurs in neuromusculoskeletal syndromes, but may also be seen as an isolated abnormality. Six families with isolated CVT were ascertained. DNA was isolated from 21 affected individuals and 17 unaffected individuals from these families, as well as from five sporadic patients with CVT. Variable expressivity was noted in three families, manifesting as clubfoot in three individuals. Genome-wide linkage analysis generated a maximum two-point logarithm of odds score on chromosome 2q with D2S1353 (Zmax = 1.43 at theta(max) = 0.1), 17 Mb from the HOXD gene cluster. DNA from one affected individual of each family was subjected to mutational analysis of the HOXD10 gene. A single missense mutation was identified (M319K, 956T > A) in the homeodomain recognition helix of the HOXD10 gene that segregated with disease in one large British family. This mutation was recently described in a family of Italian descent with CVT and Charcot-Marie-Tooth deformity HOXD10 gene mutations were not identified in any of the other families or sporadic patients with CVT, suggesting that genetic heterogeneity underlies this disorder.