Both familial isolated and Wilms tumour, bilateral sporadic aniridia, genitourinary abnormalities and mental retardation syndrome-associated aniridia have been traced to a mutation of the PAX6 gene on band 11p13.
Twelve aniridia patients, five with a family history and seven presumed to be sporadic, were exhaustively screened in order to test what proportion of people with aniridia, uncomplicated by associated anomalies, carry mutations in the human PAX6 gene.
Mutations in the human PAX6 gene produce various phenotypes, including aniridia, Peters' anomaly, autosomal dominant keratitis and familial foveal dysplasia.
Mutations in PAX6 are responsible for human aniridia and have also been found in patients with Peter's anomaly, with congenital cataracts, with autosomal dominant keratitis, and with isolated foveal hypoplasia.
Deletions of chromosome 11p13 that affect both PAX6 (aniridia) and WT1 (Wilms tumor) loci are the basis for the association of these two uncommon disorders.
Some aspects of the phenotype of aniridia appear to correlate with the predicted effect of point mutations on the paired and PST domains of the PAX6 protein.
These missense mutations give rise to haploinsufficiency by another route, because the missense mutations presented here resulted in an aniridia phenotype indistinguishable from that caused by a heterozygous deletion of the entire PAX6 gene.
Here we present four novel PAX6 missense mutations, two in association with atypical phenotypes: ectopia pupillae (displaced pupils) and congenital nystagmus (searching gaze), and two in association with more recognizable aniridia phenotypes.
This indicates that there is a heavy ascertainment bias in the selection of patients for PAX6 mutation analysis and that the 'missing' PAX6 missense mutations frequently may underlie phenotypes distinct from textbook aniridia.
Here we describe a mutational analysis of 27 Danish patients using a dideoxy fingerprinting method, which identified PAX6 mutations in 18 individuals with aniridia.
The PAX6 gene is involved in ocular morphogenesis, and PAX6 mutations have been detected in various types of ocular anomalies, including aniridia, Peters anomaly, corneal dystrophy, congenital cataract, and foveal hypoplasia.
These disease/gene matches include the oculorenal syndrome and PAX2; aniridia and PAX6; Rieger syndrome and RIEG1/PITX2; cyclopia and Sonic hedgehog; cone-rod dystrophy, Leber's congenital amaurosis and CRX; and recessive septooptic dysplasia and HESX1.