Clinical Sciences
CRYAB gene mutation analysis in a Chinese family with congenital posterior polar cataract
Suhua Zhang, Yuduan Gao, Zhe Zhang
Published 2015-04-10
Cite as Chin J Exp Ophthalmol, 2015, 33(4): 333-337. DOI: 10.3760/cma.j.issn.2095-0160.2015.04.009
Abstract
BackgroundAbout 50% congenital cataract is associated with inheritance, and the autosomal dominant (AD) inheritance is the most common mode. At least 39 candidate genetic locus and 26 cataract-related genes have been identified to be relevant with AD congenital cataract (ADCC). To identify the disease-causing gene is important.
ObjectiveThis study was to identify the mutation gene in a three-generation Chinese family with AD congenital posterior polar cataract.
MethodsA Chinese family of AD congenital posterior polar cataract was investigated in Shanxi Eye Hospital from June to December in 2009. Nineteen families were included in this pedigree with 8 patients and 11 normal phenotypes. Regular ocular examinations were performed and 8 ml periphery blood simples were collected for the extraction of DNA under the informed consent in each subject. PCR amplification and allele detection were carried out in microsatellite markers. Logarithm of the odds (LOD) scores were calculated using the linkage analysis of 21 polymorphic microsatellite markers in the region of chromosome of 1q21-25, 1p22.3, 2q33-36, 11q22.1-23.21, 7q11-12, 21q22.3, 22q11.2-12.1.Mutations were detected by DNA sequence analysis of the candidate genes. Mutation pathogenicity was predicted by PolyPhen2 software for new mutations with the risk intensity from 0 to 1.
ResultsEight ADCC patients distributed in each generation with the similar subjects in male and female members, complying with the AD mode. Linkage analysis showed the maximal limit of detection (LOD) scores of 4.06 (θ=0) in microsatellite marker D11S3178. Haplotype analysis showed that the candidate gene located in the region between D11S4176 and D11S908. Direct DNA sequence of CRYAB revealed a T–>C mutation at nucleotide 209, resulting in a novel 209 T–>C (p.Leu 70 Pro) mutation. Analysis with polyphen-2 software indicated that this new mutation caused the damage of structure and function of encoded protein (prediction score=0.996).
ConclusionsA missense mutation of the CRYAB gene is the major cause of AD congenital posterior polar cataract in this family.
Key words:
Cataract/congenital; Genetic association studies; Pedigree; China; DNA mutational analysis; Logarithm of the odds score; Microsatellite marker; alpha-Crystallin B chain
Contributor Information
Suhua Zhang
Shanxi Eye Hospital, Taiyuan 030002, China
Yuduan Gao
Zhe Zhang
