Aniridia 2

Clinical Characteristics
Ocular Features: 

A 17-year-old male with this condition was diagnosed at the age of two years with bilateral iris hypoplasia.  Cataracts were seen at the age of 17 years.  There was no foveal depression.

In a 5 generation Chinese family there were additional signs including optic atrophy, ectopia lentis, pigmentary retinopathy, and 'dysplasia' of the trabecular meshwork in 5 members.

Systemic Features: 

No systemic abnormalities have been reported.  A single extensively studied patient, who had no developmental problems, was normal by renal ultrasound, audiometric studies, and neurologic evaluations.


Autosomal dominant aniridia is the result of PAX6 (a transcription regulator gene) dysfunction.  In the majority of cases there are mutations in the PAX6 gene itself as in AN1.  There are reports, however, of familial aniridia in which direct PAX6 mutations have been excluded.  Two additional forms of aniridia in which there are alterations in genes that modulate the expression of PAX6 have been reported.  AN2 described here with mutations in ELP4 (a nucleotide variant within an intron of the ELP4 gene (11p13) located distal to the 3-prime end of the PAX6 gene, plus AN3 (617142) with mutations in TRIM44.  Both ELP4 and TRIM44 are regulators of the PAX6 transcription gene.

Aniridia 2 has been reported in one patient with a nucleotide variant within an intron of the ELP4 gene (11p13) located distal to the 3-prime end of the PAX6 gene.  The gene product is a cis-regulatory enhancer.  

Other evidence for aniridia resulting from regulatory modification of PAX6 gene function comes from families in which there are structural alterations such as deletions in chromosome 11, downstream of the PAX6 gene location.

Treatment Options: 

Treatment has not been reported.

Article Title: 


Bhatia S, Bengani H, Fish M, Brown A, Divizia MT, de Marco R, Damante G, Grainger R, van Heyningen V, Kleinjan DA. Disruption of autoregulatory feedback by a mutation in a remote, ultraconserved PAX6 enhancer causes aniridia. Am J Hum Genet. 2013 Dec 5;93(6):1126-34. Review.

PubMedID: 24290376

Cheng F, Song W, Kang Y, Yu S, Yuan H. A 556 kb deletion in the downstream region of the PAX6 gene causes familial aniridia and other eye anomalies in a Chinese family. Mol Vis. 2011 Feb 10;17:448-55.

PubMedID: 21321669