Objective: To report Avellino corneal dystrophy and underlying R124H mutation in 2 families of Indian origin.
Methods: Peripheral blood was collected in EDTA for genomic DNA isolation from leukocytes of all affected and unaffected individuals. Amplification of transforming growth factor beta-induced gene (TGFBI) using polymerase chain reaction followed by direct sequencing was carried out to determine the mutations underlying the disorder. A detailed clinical evaluation was undertaken to establish a genotype-phenotype correlation.
Results: R124H mutation resulting from a missense heterozygous substitution of G to A at nucleotide 418 of TGFBI was detected in all affected members of the 2 families. The affected individuals were clinically diagnosed as having granular corneal dystrophy. Histopathological examination was not done because no surgical intervention was undertaken.
Conclusions: To our knowledge, this is the first report of Avellino corneal dystrophy from India clinically diagnosed as granular corneal dystrophy, emphasizing that TGFBI screening is essential for the accurate diagnosis and classification of corneal dystrophies.
Clinical relevance: Molecular genetics is a useful tool for accurate diagnosis and classification of corneal dystrophies. All autosomal dominant stromal dystrophies should be screened for underlying mutations in TGFBI because the clinical and phenotypic appearance is variable.