Objective: To detect gene mutations in a Chinese family with primary erythermalgia. Methods: Mutations in SCN9A gene were detected by PCR amplification of the 26 coding exons of SCN9A and sequencing of the PCR products, and compared the sequences in this family with the sequence from gene database. Results: A new mutation was found in this pedigree, and the cytosine in the base number 2572 of this gene was replaced by thymine with the corresponding amino acid leucine replaced by phenylalanine. Conclusions: A new mutation is detected in this family, and new evidence has been found to prove the SCN9A is the responsible gene for primary erythermalgia. Also, this finding is helpful to investigate the mechanism of this disease and provide evidence to treat it.

目的 对原发性红斑性肢痛症的致病基因进行定位及突变研究.方法收集一个原发性红斑性肢痛症家系成员和一个散发病例的血样抽提基因组DNA.选用2号染色体长臂上已知致病区域的6个微卫星标记对该家系成员进行基因扫描,并对基因分型结果进行连锁分析及单倍型分析.PCR扩增SCN9A基因的全部外显子,并进行测序.针对所发现的突变以Hph Ⅰ、BsrS Ⅰ内切酶行限制性片段长度多态性(RFLP)分析.结果连锁分析结果发现本家系在微卫星标记D2S2370和D2S2330的两点最大LOD值为2.11(重组率=0.00),单倍型分析发现本家系在微卫星标记D2S1353和D2S2345存在重组.家系患者和散发病例均存在SCN9A基因第15外显子的错义杂合点突变:家系全部患者均存在T2573A杂合突变,散发病例存在T2543C杂合突变,分别导致Nav1.7第858位的亮氨酸被替换为组氨酸(L858H)及第848位的异亮氨酸被苏氨酸替换(I848T).RFLP证实了正常对照无此突变.结论在世界上首次证明SCN9A基因是原发性红斑性肢痛症的候选致病基因。