Best卵黄样黄斑营养不良一家系的临床表型特征和基因研究

目的 探讨Best卵黄样黄斑营养不良(BVMD)一家系的临床表型特征和相关基因VMD2的突变特点.方法 回顾性分析BVMD一家系患者详细的临床资料,包括眼底检查、荧光素眼底血管造影(FFA)及相干光断层扫描(OCT)图像等,并对患眼病变进行分期.同时对该家系5例患者及其家族中2名正常成员进行基因分析.采取外周血2.7 ml,制备外周血白细胞基因组DNA,应用合成的特异性引物,以聚合酶链反应(PCR)分别扩增VMD2基因的第1～11对外显子,将基因产物进行直接测序,分析相应基因序列.结果 该家系呈现常染色体显性遗传.5例(10只眼)眼底病变分别属于0、Ⅱ a、Ⅱb、Ⅲ和Ⅳ期,较为少见.各期的眼底改变、FFA和OCT图像特征虽不相同,但具有代表性.基因序列分析可见VMD2基因第301密码子第3个碱基呈杂合子点突变,即T→G,导致天冬氨酸变为谷氨酸(Asp301Glu).结论 我国BVMD一家系呈现VMD2基因突变.基因分析结果将为疾病的确诊提供可靠依据.

Clinical manifestations and gene analysis in one Chinese family with Best vitelliform macular dystrophy

OBJECTIVE: To describe clinical phenotype in a Chinese family with Best vitelliform macular dystrophy (BVMD) and to identify the mutation of the VMD2 gene in this family. METHODS: It was a retrospective case analysis. Five patients (10 eyes) were diagnosed as BVMD by the fundus photography, EOG, fluorescein angiography (FFA) and optical coherence tomography (OCT). Their clinical data were analyzed retrospectively. Molecular genetic analysis was performed on DNA extracted from peripheral leucocytes of all patients and 2 unaffected family members. Exon 1 to 11 of the VMD2 gene were amplified by polymerase chain reaction for direct sequencing. RESULTS: The pedigree showed an autosomal dominant inheritance. Ten eyes from 5 patients were classified into Stage 0, II a, II b, III and IV with different clinical manifestations. Direct sequencing of all affected members revealed a T-->G transition at codon 301, producing Asp301Glu mutation of VMD2 gene. CONCLUSIONS: Asp301Glu mutation of the VMD2 gene is found in a Chinese family with BVMD. The phenotype of BVMD in this family belongs to geographic type. Molecular genetic approach may be useful for the proper diagnosis of BVMD.