Anterior Segment Dysgenesis 8

A number sign (#) is used with this entry because of evidence that anterior segment dysgenesis-8 (ASGD8), is caused by homozygous or compound heterozygous mutation in the CPAMD8 gene (608841) on chromosome 19p13.

Description

Anterior segment dysgeneses (ASGD or ASMD) are a heterogeneous group of developmental disorders affecting the anterior segment of the eye, including the cornea, iris, lens, trabecular meshwork, and Schlemm canal. The clinical features of ASGD include iris hypoplasia, an enlarged or reduced corneal diameter, corneal vascularization and opacity, posterior embryotoxon, corectopia, polycoria, an abnormal iridocorneal angle, ectopia lentis, and anterior synechiae between the iris and posterior corneal surface (summary by Cheong et al., 2016).

Clinical Features

Cheong et al. (2016) studied 4 patients from 3 unrelated families with an 'unusual' form of anterior segment dysgenesis that the authors stated did not fit with any previously described ASGD criteria. All affected individuals shared predominant iris and lens abnormalities, including iris hypoplasia, iris transillumination defects, ectropion uveae, corectopia, iridodonesis with ectopia lentis, and cataracts. No retinal abnormalities or extraocular phenotypes were observed.

Molecular Genetics

By whole-exome sequencing in the probands from 3 families with anterior segment dysgenesis limited to the iris and lens, Cheong et al. (2016) identified homozygosity and compound heterozygosity for mutations in the CPAMD8 gene (see, e.g., 608841.0001-608841.0003) that segregated with disease in the families.