Novel human CRYGD rare variant in a Brazilian family with congenital cataract

PURPOSE To describe a novel polymorphism in the γD-crystallin (CRYGD) gene in a Brazilian family with congenital cataract. METHODS A Brazilian four-generation family was analyzed. The proband had bilateral lamellar cataract and the phenotypes were classified by slit lamp examination. Genomic DNA was extracted from peripheral blood and coding regions and intron/exon boundaries of the αA-crystallin (CRYAA), γC-crystallin (CRYGC), and CRYGD genes were amplified by polymerase chain reaction and directly sequenced. RESULTS Sequencing of the coding regions of CRYGD showed the presence of a heterozygous A→G transversion at c.401 position, which results in the substitution of a tyrosine to a cysteine (Y134C). The polymorphism was identified in three individuals, two affected and one unaffected. CONCLUSIONS A novel rare variant in CRYGD (Y134C) was detected in a Brazilian family with congenital cataract. Because there is no segregation between the substitution and the phenotypes in this family, other genetic alterations are likely to be present.