PITX3 and Developmental cataract: 2002). All three members of the PITX family, but predominantly PITX2 and PITX3, are expressed in the anterior segment of the eye. In humans, PITX2 mutations are associated with Axenfeld‐Rieger syndrome and PITX3 mutations with congenital cataracts (Semina et al. 1998). PITX1 is also essential for hindlimb and pituitary development (Szeto et al. 1999), and PITX2 for tooth, heart, lung and abdominal development in the mouse (Lin et al. 1999).