角膜营养不良与BIGH3基因突变研究

Analysis of mutation of BIGH3 gene in Chinese patients with corneal dystrophies

目的 对角膜营养不良患者进行分子遗传学分析 ,探讨我国人角膜营养不良中BIGH3基因突变的类型。方法 2 0 0 0年 7～ 1 2月收集 1 5例颗粒状、Avellino、Reis B櫣ｃｋｌｅｒｓ角膜营养不良患者和 5例无任何角膜病变的正常对照者外周血 1 0ml,提取白细胞DNA ,利用合成的BIGH3基因第 4和第 1 2外显子特异性引物 ,进行PCR扩增 ,并对扩增产物进行直接测序 ,分析相应基因序列。结果1 5例患者均检出BIGH3基因突变 ,其中R1 2 4H突变 1 0例 ,包括纯合子 2例 ,杂合子 8例 ;R1 2 4L突变 2例 ,均为杂合子 ;R555W突变 3例 ,均为杂合子 ;正常对照者均未检出BIGH3基因突变。结论1 5例角膜营养不良患者的角膜病变均由BIGH3基因突变引起 ,与国外文献报道相同。突变基因对角膜病变严重程度的影响具有剂量效应 ,纯合子病情严重。R1 2 4L突变患者的临床表现重于R1 2 4H突变患者。

Objective To study whether Chinese patients with various corneal dystrophy carry mutations in BIGH3 gene. Methods Genomic DNA was extracted from Chinese patients with Avellino corneal dystrophy (ACD, 10 cases) , Reis Bücklers corneal dystrophy (CDRB, 2 cases), granular corneal dystrophy (GCD, 3 cases) and 5 control subjects. The exons 4 and 12 of BIGH3 gene were amplified by PCR and the product was sequenced directly. Results All 15 patients carried mutations in BIGH3 gene, R124H in 10 cases with ACD, R124L in 2 cases with CDRB and R555W in 3 cases with GCD. Conclusions Corneal lesions in all 15 Chinese patients clinically diagnosed with corneal dystrophies are caused by mutations in BIGH3 gene. Dose effect analysis shows that corneal lesions are more severe in homozygous patients than those in heterozygous cases and that clinical manifestation of patients with R124L mutation is more severe than that of patients with R124H mutation.