Clinical Characteristics
Ocular Features
There is complete absence of the lens and with it aplasia of the anterior segment including complete absence of the iris, ciliary body, and trabecular meshwork. In an autopsied case, the cornea was thinned and lacked endothelium, Bowman layer, and Descemet membrane while the retina was dysplastic. In the single family reported, 2 sibs had sclerocornea and one had megalocornea. Normal pressure was reported in several eyes but a single eye in one patient at the age of 3 years developed buphthalmos with elevated pressure.
Systemic Features
No systemic abnormalities have been reported.
Genetics
Inheritance
Homozygosity of a nonsense mutation in the FOXE3 transcription factor gene (1p32) seems to be responsible for this autosomal recessive disorder. The same gene has been implicated in rare cases of Peters anomaly (604229) and in anterior segment mesenchymal dysgenesis (107250).
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.