Molecular analysis of FOXC1 in subjects presenting with severe developmental eye anomalies

Haploinsufficiency through mutation or deletion of the forkhead transcription factor, FOXC1, causes Axenfeld-Rieger anomaly, which manifests as a range of anterior segment eye defects and glaucoma. The aim of this study is to establish whether mutation of FOXC1 contributes toward other developmental eye anomalies, namely anophthalmia, microphthalmia, and coloboma.

The coding sequence and 3;-UTR of FOXC1 was analyzed in 114 subjects with severe developmental eye anomalies by bidirectional direct sequencing.

Four coding FOXC1 variations (two novel missense variations, one insertion, and one novel deletion) were identified in the cohort. Two noncoding variations were also identified in the 3'-UTR. The missense mutations were c.889C_T and c.1103C_A, resulting in p.Pro297Ser and p.Thr368Asn, respectively. The c.889C_T transition was identified in 19 of the 100 unaffected control samples. The c.1103C_A transversion resulted in a conservative substitution in an unconserved amino acid and was deemed unlikely to be pathogenic. A c.1142_1144insGCG change resulting in p.Gly380ins, which was previously associated with kidney anomalies, was identified in 44 of the 114 affected individuals. This variation was also present in 29 of the 87 unaffected controls and is therefore likely to be a polymorphism. A c.91_100delCGGCGGCCG deletion resulting in p.Ala31_33del was identified in one individual. This deletion segregated with the moderately affected mother and unaffected maternal grandfather of the proband. This deletion was identified in one of the 307 unaffected controls.

Our data suggests a potential susceptibility role for FOXC1 in generating severe eye pathologies. However, on the basis of these results, it is unlikely that FOXC1 mutation is a major causative factor of anophthalmia, microphthalmia, and coloboma.