An R124C mutation in TGFBI caused lattice corneal dystrophy type I with a variable phenotype in three Chinese families

PURPOSE A genetic and clinical study of three unrelated Chinese pedigrees with a variable phenotype of lattice corneal dystrophy type I (LCD I). METHODS The eyes of the patients were examined by slit lamp microscopy, and other clinical records were also collected. Genomic DNA was extracted from peripheral leukocytes of the affected patients and their family members. Exons of the transforming growth factor beta induced TGFBI gene were amplified by polymerase chain reaction and directly sequenced to verify the mutation. Fifty healthy volunteers were analyzed as normal controls. RESULTS Variable atypical clinical features of LCD I were found by slit lamp microscopy in these three Chinese pedigrees. A heterozygous single base-pair transition from C to T (C417T), leading to amino acid substitution (R124C) in the encoded TGFBI protein, was detected in all of the affected patients. No mutation was found in unaffected family members and 50 normal controls. CONCLUSIONS Clinical features of Chinese patients with the same R124C mutation are quite variable even within the same family. Molecular genetic analysis of TGFBI can offer a rapid, accurate diagnosis of patients with atypical corneal dystrophies.