The point mutation and polymorphism in keratoconus candidate gene TGFBI in Chinese population.

OBJECTIVE

To understand the region point mutations and single nucleotide polymorphisms characteristic of keratoconus candidate gene in Chinese population, the TGFBI.

METHODS

Polymerase chain reaction-single strand conformation polymorphism and DNA direct sequencing were performed on blood samples from 30 cases of keratoconus patients and 30 normal controls. 17 exons from the coding region of TGFBI gene were examined for point mutations and single nucleotide polymorphisms.

RESULTS

Two types of base mutation were found in exon 12, which were both heterozygous. In 1 patient the site 535 showed GGA→TGA substitution, which was the change from glycine to stop codon (G535X). This was not found in all control cases. In 2 patients and 1 control case the site 540 showed TTT→TTC substitutions without changing of the coding for phenylalanine (F540F), suggesting for the polymorphism.

CONCLUSION

The candidate keratoconus gene TGFB1 showed genetic variation and mutation in keratoconus population. The gene might play a role in the development of keratoconus in Chinese population.