Abstract
Abstract: :
Purpose: To verify mutations in TGFßI gene in Brazilian families with corneal dystrophies. Method: Fifty-seven members of two Brazilian kindreds of corneal dystrophies were clinically examined and molecular analysis of the TGFßI gene was performed in seventeen patients, thirteen belonging to one Brazilian kindred with clinical features of granular and Avellino dystrophies and four members of a family with an asymmetric, late-onset form of lattice corneal dystrophy. Mutation analysis was carried out on all individuals for exons 4, 12 and 14 through PCR followed by Strand Single Conformation Polimorphysm (SSCP) and automated sequencing. Results: The known R555W mutation on exon 12 was detected on eight patients with clinical features of granular and Avellino corneal dystrophies. A novel missense mutation, V624M, was identified on exon 14, in a region of kerathoepithelin protein containing two previously reported changes: N622H and H626R, of the two individuals affected sibs by lattice corneal dystrophy but not in two healthy relatives. This alteration was also not found in a 130-chromosome control sample, confirming that it is a pathogenic change. Conclusion: The finding of R555W mutation on the Avellino phenotype suggests that there is a spectrum of clinical variability associated with mutations in the TGFßI gene. On the other hand, the clustering of N622H, H626R and V624M, described for the first time, points to an important biological function of this segment of the kerathoepithelin protein for amyloid precipitation
Keywords: 476 molecular biology • 385 degenerations/dystrophies • 417 gene/expression