ABSTRACT
Background Inheritance is one of main causing-disease factors in congenital cataract.So the screen of causing-disease gene in congenital cataract patients is a critical step.Objective This survey was to investigate the molecular characteristics of a Chinese pedigree with a special crystalline autosomal dominant congenital cataract(ADCC) in Shanxi province.Methods This study was approved by Ethic Commission of Shanxi Eye Hospital.Informed consent was obtained from each subject before any medical examination.Twenty-two families from a pedigree with special crystalline were included in this study.The family members received regular ophthalmologic and general examinations to rule out any concomitant disorders.Blood samples were obtained to extract the DNA from all the subjects.Twenty-two fluorescent labeled microsatellites were selected from 17 causing genes of ADCC and amplified and screened for the linkage analysis.LOD was calculated and the candidate gene was directly sequenced.Results Ten individuals with congenital cataract were found in the family with the similar phenotype.The inheritance mode complied with the autosomal dominant pattern.Linkage analysis indicated a gene chain at D2S325 and D2S2358 with the LOD value 1.20(θ =0) and 0.22(θ =0).A known c.C70A(p.P23T) missence mutation at the coding region of CRYGD gene was detected by direct sequence.Conclusions A missense mutation P23T of the CRYGD gene cause the autosomal dominant congenital nuclear cataract with the special phenotype.