RESUMO
<p><b>OBJECTIVE</b>To investigate the transforming growth factor beta induced (TGFBI; BIGH3) gene mutation and founder effect of two large Chinese families clinically diagnosed as Thiel-Behnke corneal dystrophy.</p><p><b>METHODS</b>Fifteen members including 13 affected and 2 healthy in family A, 14 members including 6 affected and 8 healthy in family B, as well as 20 other unrelated healthy individuals were tested for TGFBI gene mutation. Haplotype analysis and clinical examination were also carried out in the two families.</p><p><b>RESULTS</b>In exon 12 of the TGFBI gene, 1664G to A change was detected in all the patients, which leads to an amino acid replacement of arginine with glutamine (p.Arg555Gln). Members of the two families share some similar haplotypes.</p><p><b>CONCLUSION</b>Genetic analysis is helpful in the diagnosis of corneal dystrophy. The two families may come from a same ancestor.</p>