Mutations in the PITX3 gene have been found to cause multiple types of cataract, which have been described as congenital total and posterior polar.
The preferred title/symbol for this entry was formerly 'Cataract, Posterior Polar, 4; ... Mutations in the PITX3 gene have been found to cause multiple types of cataract, which have been described as congenital total and posterior polar. The preferred title/symbol for this entry was formerly 'Cataract, Posterior Polar, 4; CTPP4.'
Berry et al. (2004) examined affected members of a 4-generation English family with autosomal dominant posterior polar cataract. The opacity, which was bilateral in all cases, consisted of a single well-defined plaque that was confined to the posterior ... Berry et al. (2004) examined affected members of a 4-generation English family with autosomal dominant posterior polar cataract. The opacity, which was bilateral in all cases, consisted of a single well-defined plaque that was confined to the posterior pole of the lens. Hospital records indicated that usually the opacity was present at birth or developed within the first few months of life and progressed, with age, to other regions of the lens. One member of the family had severe anterior segment mesenchymal dysgenesis (ASMD; see 107250) in addition to posterior polar cataract; all other affected members had only posterior polar cataract and no other ocular or systemic abnormalities. Berry et al. (2004) investigated another 4-generation family of English descent with posterior polar cataract in which 4 of 11 affected members also had ASMD but no other clinical abnormalities. The authors also studied 3 large families of English, Chinese, and Hispanic descent in which all affected individuals had progressive posterior polar cataract and no other abnormalities. Bidinost et al. (2006) reported a 3-generation Lebanese family in which 26 members had posterior polar cataract. Two affected brothers from a consanguineous mating in this family had a more severe phenotype. In addition to posterior polar cataract, they had severe bilateral microphthalmia, blindness, and a neurologic disorder characterized by mental retardation, choreiform movements, and increased muscle tone and decreased deep tendon reflexes of the lower extremities. Imaging studies in these brothers revealed no gross abnormalities of brain development.
Semina et al. (1998) screened a collection of 80 DNA samples from individuals with various eye anomalies for mutations in the PITX3 gene. In a mother and son with congenital total cataract, they identified a heterozygous missense mutation ... Semina et al. (1998) screened a collection of 80 DNA samples from individuals with various eye anomalies for mutations in the PITX3 gene. In a mother and son with congenital total cataract, they identified a heterozygous missense mutation (S13N; 602669.0002) and in an unrelated patient with anterior segment mesenchymal dysgenesis (ASMD; 107250) and cataracts, they identified a heterozygous 17-bp insertion (602669.0001). In affected members of 4 large unrelated families with autosomal dominant posterior polar cataract, 3 of English descent and 1 of Chinese descent, Berry et al. (2004) identified heterozygosity for a 17-bp duplication in the PITX3 gene (602669.0001). In affected members of a 4-generation family of Hispanic descent with posterior polar cataract, Berry et al. (2004) identified heterozygosity for a 1-bp deletion in the PITX3 gene (650delG; 602669.0003). Bidinost et al. (2006) identified heterozygosity for the 650delG mutation in the PITX3 gene in 26 members with posterior polar cataract in a 3-generation Lebanese family. Two affected brothers from a consanguineous mating in this family were homozygous for the deletion and had a more severe phenotype. In addition to posterior polar cataract, they had severe bilateral microphthalmia, blindness, and a neurologic disorder characterized by mental retardation, choreiform movements, and increased muscle tone and decreased deep tendon reflexes of the lower extremities.