常染色体显性遗传视网膜色素变性家系的基因筛查

Screening of candidate genes in a family with autosomal dominant retinitis pigmentosa

目的 确定一个常染色体显性遗传视网膜色素变性 (autosomaldominantretinitispigmentosa ,ADRP)家系的致病基因及其突变位点和类型。方法 应用聚合酶链反应 单链构象多态性结合DNA测序技术 ,对来自同一家系的 4例RP患者及 4名正常人外周血DNA进行分子遗传学分析 ,筛查 3个候选基因共 8个外显子。结果 来自同一家系的 4例RP患者均发现有视紫红质基因 (rhodopsin ,RHO)第 1外显子第 5 2密码子存在TTC→TAC的点突变 (Phe5 2Tyr) ,而 4名正常人未发现这种突变。结论 在这个中国ADRP大家系中 ,发现RHO基因的致病突变 ,表明ADRP存在明显遗传异质性。

Objective: To determine the causative mutation in a 5-generation pedigree with autosomal dominant retinitis pigmentosa (ADRP). Methods: Genomic DNA from four patients and 4 normal persons in the same pedigree suffering ADRP were extracted, and subsequently eight exons of three ADRP candidate genes were screened for mutations by a combined polymerase chain reaction-single strand conformation polymorphism and DNA sequencing techniques. Results: A new point mutation in rhodopsin gene at codon 52 of exon 1 (TTC&rarrTAC) that resulted in a substitution of Tyr to Phe was detected in the four affected family members, but not in the four control individuals from the same pedigree. Conclusion: A causative mutation of rhodopsin gene was identified in a large Chinese pedigree with ADRP. The present study confirmed the molecular genetic heterogeneity of ADRP.