A novel nonsense mutation with a compound heterozygous mutation in TGFBI gene in lattice corneal dystrophy type I

We examined transforming growth factor beta-induced (TGFBI) gene mutations in a family with lattice corneal dystrophy type I.

The proband was one of the offspring of a consanguineous marriage; 4 affected and 3 unaffected individuals of the family were investigated. Genomic DNA of each case was extracted and used for polymerase chain reaction (PCR). The exon 4, 11, and 12 of the TGFBI gene were directly sequenced. The mutations were confirmed by PCR restriction fragment length polymorphism analysis.

There was no significant difference in phenotype between the proband and the other 2 patients, except for progression of the corneal opacity with age. R124C mutation was detected in all affected individuals. In addition, G470X, a novel nonsense mutation, was detected in the proband, resulting in the proband being a compound heterozygote with the TGFBI gene. Her unaffected daughter was found to be heterozygous for G470X.

It is most likely that the novel nonsense mutation is not pathogenic, and that the mutant keratoepithelin protein with R124C is responsible for the phenotype.