Methods and compositions for the diagnosis and treatment of cataracts

The invention provides nucleic acids encoding Pitx3 polypeptides, fragments thereof and homologs thereof and Pitx3 polypeptides encoded thereby. Pitx3 polypeptides play an important role in development of eye structures, e.g., the lens, and was shown herein to be associated with the formation of cataracts and Anterior Segment Mesenchymal Dysgenesis (ASMD). Thus, the invention provides methods for predicting whether a subject has or is at risk of developing cataracts or other disease associated with an aberrant Pitx3, by determining, e.g., whether the subject has a genetic lesion in a Pitx3 gene, such as a 17 bp insertion, characteristic of cataract development and ASMD or a base pair substitution at codon 13. Methods for treating cataracts or diseases or conditions associated with an aberrant Pitx3, e.g., by administering to the subject a Pitx3 therapeutic, are also disclosed, as well as assays for identifying Pitx3 therapeutics.