PITX3 and miotic rate: Mutation screening of PITX3 for the two affected siblings with the common phenotype of congenital cataract associated with MR did not reveal any mutation in the four exons of PITX3. Sequence analysis of the affected siblings, their normal sisters, and their mother showed substitution polymorphisms (c.439C>T and c.930C>A; we considered the first nucleotide of the cDNA sequence nucleotide number one), in exons 3 and 4, respectively, that were not included in a conserved domain of PITX3 and did not segregate with the disease.