肥厚型心肌病样临床表现的Fabry病家系研究

目的对一个临床表现酷似肥厚型心肌病的Fabry病家系进行α-半乳糖苷酶（α-GalA）基因测序并发现其突变形式。方法该家系成员共15例,经过询问病史、体格检查、心电图及超声心动图检查,抽取外周静脉血标本,提取白细胞基因组DNA,PCR分段扩增α-GalA基因的7个外显子序列,产物纯化后直接测序,分析筛查基因的突变位点。结果家系中有9例发生α-GalA基因新的错义突变,突变位点位于α-GalA基因第5外显子的第32号密码子,均由TGG变为TGA,TGA为终止密码子,故可引起TGG正常编码的色氨酸残基编码中断。其中6例女性为带有突变基因的杂合子,3例男性为带有突变基因的半合子。9例患者中6例患有心肌肥厚。家系中正常人无此类突变。结论对心肌肥厚患者应与Fabry病进行鉴别诊断。α-GalA基因突变检测可用于Fabry病患者及其亲属,以明确诊断和进行病因学治疗。

Alpha-galactosidase A gene mutation in a Chinese family with Fabry disease mimicking clinical features of hypertrophic cardiomyopathy

OBJECTIVE: To screen gene mutation in alpha-galactosidase A (alpha-Gal A) in a nonconsanguineous Chinese family with Fabry disease (FD) with clinical manifestations similar to hypertrophic cardiomyopathy (HCM). METHODS: Mutation analysis was performed by using purified PCR products to direct sequence analysis on an ABI-377XL automated DNA sequencer. DNA analysis of alpha-Gal A gene and physical and clinical examinations were performed in a female proband and in her relatives (15 subjects in total). RESULTS: Three hemizygotes and 6 heterozygotes were diagnosed for FD by the alpha-Gal A gene analysis with a missense mutation in exon 5 of the alpha-Gal A sequence, leading to a TGG32TGA substitution, which may induce the absent of tryptophan's translation (corresponded to TGG) by the terminator codon TGA. Six patients in the family were revealed as HCM by echocardiography. CONCLUSIONS: Present results show that it is important to differentiate FD from other causes of hypertrophy in patients with cardiac hypertrophy. Screening for alpha-Gal A gene mutations in patients with FD and in their relatives could help to identify all suspected cases within the families.