Evaluation of CAND2 and WNT7a as Candidate Genes for Congenital Idiopathic Clubfoot

Congenital idiopathic clubfoot is a common pediatric musculoskeletal deformity with no known etiology. The deformity reportedly follows a Mendelian pattern of inheritance. Recent work has demonstrated linkage in chromosome 3 and 13 in a large, multigeneration, highly penetrant family with idiopathic clubfoot. From the linkage region on chromosome 3, we selected the candidate genes CAND2 and WNT7a, which are involved in lower extremity development, and hypothesized mutations in these genes would be associated with the phenotype of congenital idiopathic clubfoot. The CAND2 gene was sequenced in 256 clubfoot patients, and 75 control patients, while WNT7a was screened using 56 clubfoot patients and 50 control patients. We found a polymorphism in each gene, but the single nucleotide change in CAND2 was a silent mutation that did not alter the amino acid product, and the single nucleotide change in WNT7a was in the upstream, non-coding or promoter region before the start codon. Based on these results it is unlikely CAND2 and WNT7a are the major genes that causes clubfoot, however WNT7a might be one of many genes that could increase susceptibility to develop clubfoot but do not directly cause it.