Project description:Syndactyly type 1 (SD1) is an autosomal dominant limb malformation characterized in its classical form by complete or partial webbing between the third and fourth fingers and/or the second and third toes. Four subtypes (a, b, c and d) are defined based on variable phenotypes, but the disease genes remain unidentified. SD1-a have been mapped to chromosome 3p21.31 and SD1-b to 2q34-q36. SD1-c and SD1-d are very rare and no gene loci are known for them. We performed linkage and haplotype analyses in two Han Chinese families with SD1-c, and refined the disease locus to 2q31- 2q32. In the large family A, mutation of c.917G>A (p.R306Q) in the homodomain of HOXD13 was indentified. Family B was confirmed with genetic homogeneity and the mutation was c.916C>G (p.R306G). CNV analysis by array CGH excluded possible microdeletion or microduplication. SD1c patient sample in the SD1c family vs common control outside the family, healthy control sample in the SD1c family vs common control outside the family
