Novel Mutations of the GLA Gene in Japanese Patients with Fabry disease and their functional characterization by active site specific chaperone

法布里病是一种由溶酶体酶α-半乳糖苷酶A(EC 3.2.1.22)缺乏引起的X连锁隐性遗传性代谢紊乱。致病突变是多样的，包括大重排和单碱基替换，分布于α-半乳糖苷酶A基因的7个外显子。法布里病的突变热点不存在。我们检查了日本的72名Fabry患者，发现了26个GLA突变，其中包括11个新的突变。已报道的一种治疗Fabry病的潜在方法是活性部位特异性伴侣疗法，在亚抑制浓度下使用α-半乳糖苷酶A的抑制剂1-脱氧半乳糖苷酶(DGJ)。我们用26个突变型谷氨酸转导COS-7细胞，并分析了α-半乳糖苷酶A的活性。然后，我们用DGJ处理转染的COS-7细胞，并分析其对突变酶活性的影响。11个错义突变体的活性随着DGJ的增加而显著增加。虽然ASSC疗法仅对错误折叠突变有用，因此并不适用于所有病例，但它可能对治疗许多日本法布里病患者有用。

Fabry disease is an X-linked recessive inborn metabolic disorder caused by a deficiency of the lysosomal enzyme α-galactosidase A (EC 3.2.1.22). The causative mutations are diverse, include both large rearrangements and single-base substitutions, and are dispersed throughout the 7 exons of the α-galactosidase A gene (GLA). Mutation hotspots for Fabry disease do not exist. We examined 72 Fabry patients in Japan and found 26 GLA mutations, including 11 novel ones. A potential treatment reported for Fabry disease is active site specific chaperone (ASSC) therapy using 1-deoxygalactonojirimycin (DGJ), an inhibitor of α-galactosidase A, at subinhibitory concentrations. We transfected COS-7 cells with the 26 mutant GLAs and analyzed the a-galactosidase A activities. We then treated the transfected COS-7 cells with DGJ and analyzed its effect on the mutant enzyme activities. The activity of 11 missense mutants increased significantly with DGJ. Although ASSC therapy is useful only for misfolding mutants and therefore not applicable to all cases, it may be useful for treating many Japanese patients with Fabry disease.