Abstract
Purpose: :
Keratoconus is a noninflammatory, corneal thinning disorder. Genetic etiology have been suggested as a cause of keratoconus. To investigate the genetic etiology of keratoconus, we were screened for genetic variations of the human transforming growth factor beta–induced gene (BIGH3), which is a major protein component in the corneal stroma.
Methods: :
Genomic DNA was extracted from blood samples of 35 affected individuals with keratoconus patients visited the Department of Ophthalmology at the Catholic University Medical Center. To screen of genetic variation, the exons 4, 11, 12, 13, and 14, which are the hot spots of BIGH3 gene were performed using polymerase chain reaction and direct sequencing.
Results: :
In this study, we found one missense mutation in BIGH3 gene. In 35 patients with keratoconus who were screened, one patient revealed a homozygous point mutation in the BIGH3 gene. And when we performed a mutation screening in patient’s family, the mother had heterozygosity for the BIGH3 gene. But she had not given diagnosis of keratoconus and any ocular disease symptom. In keratoconus, the single–base pair substitution (G to T) results in an amino acid substitution (Arg514Leu) in exon 11 of the BIGH3 gene. The cornea with the mutation was shown atypical histopathologic features for keratoconus. Other coding region had no mutation.
Conclusions: :
Our study is the first report of missense mutation, Arg514Leu, of BIGH3 gene in Korean patient with keratoconus. It is suggested that the heterozygous alteration of the BIGH3 gene is responsible for causing keratoconus in this family.
Keywords: cornea: basic science • gene screening