Mutations in the Pitx1 gene or its surrounding regulatory regions are also associated with avian foot feathering (Domyan et al., 2016) and several human limb abnormalities, including polydactyly (Klopocki et al., 2012), Liebenberg syndrome (Spielmann et al., 2012), and familial clubfoot (Gurnett et al., 2008). This evidence concerns the gene PITX1 and Brachydactyly - elbow wrist dysplasia.