Purpose: To report a novel V505D mutation of the human transforming growth factor beta-induced (TGFBI) gene found in a Chinese family with lattice corneal dystrophy, type I (LCDI).
Methods: Genomic DNA was extracted from peripheral leukocytes from eight affected and four unaffected members of a Chinese family with LCDI. Exons of the TGFBI gene were amplified by polymerase chain reaction and directly sequenced. Fifty normal Chinese individuals were also analysed as controls. Histopathological examination of a corneal button was performed after keratoplasty of the proband.
Results: A heterozygous single-base-pair transversion (GTC to GAC, valine to aspartic acid) at codon 505 in exon 11 of the TGFBI gene (V505D) was detected in all of the affected members. No mutation was found in the unaffected members or in the 50 normal controls. The mutation cosegregated with the disease phenotype throughout three generations. Although a slit-lamp examination showed features of LCDI in most cases, the age at onset of the symptoms was several years later than that in cases of LCDI with an R124C mutation. By histopathological examination, numerous amyloid deposits were observed in the stroma, including beneath Bowman's membrane.
Conclusion: A novel V505D mutation in the TGFBI gene causes LCDI in this Chinese family. It is the fourth reported mutation of the TGFBI gene associated with LCDI.