遗传性痉挛性截瘫患者MJD1基因的突变分析

目的探讨中国汉族人群中遗传性痉挛性截瘫(Hereditary Spastic Paraplegia,HSP或SPG)患者的MJD1基因突变特点,进一步探索HSP和遗传性脊髓小脑性共济失调(Spinocerebellar Ataxia,SCA)的遗传和临床异质性。方法应用聚合酶链反应、8%变性聚丙烯酰胺凝胶电泳和DNA T载体连接测序等方法对78例临床诊断为HSP的患者进行MJD1基因突变分析。结果在18个HSP家系中检出SCA3/MJD1家系2个,占11.1%,该2例家系均为常染色体显性遗传,2例家系先证者在临床上符合HSP的诊断标准,突变的MJD1等位基因CAG三核苷酸异常重复次数分别为65和69次,散发的HSP病例未发现MJD1等位基因的异常。结论HSP和SCA都具有明显的临床和遗传异质性,其表型在临床上有相互交叉现象,部分SCA3/MJD1患者临床上可为典型的痉挛性截瘫特征而无任何明显的共济失调表现。对临床表现为HSP的患者,尤其是有明显阳性家族史的患者进行MJD1基因诊断可以弥补HSP临床诊断的不足。

MJD1 gene mutation analysis of hereditary spastic paraplegia

Objective To investigate the mutation characteristics of MJD1 gene in Chinese Han patients with hereditary spastic paraplegia(HSP),and research the genetic and clinical heterogeneity of the HSP and SCA patients.Methods We analyzed MJD1 gene nucleotide repeat number in 78 clinical diagnostic HSP cases using PCR,8% denaturing polyacrylamide gel and T carrier sequencing methods.Results We found two autosomal dominant SCA3/MJD1 family constellations from 18 HSP families(11.1%).The two family constellations were diagnosed by clinical standard of HSP,and the CAG trinucleotide repeat numbers of the mutational MJD1 allele were 65 and 69 respectively.At the same time we did not find the abnormal MJD1 allele in sporadic HSP patients.Conclusions HSP and SCA comprise a group of clinically and genetically heterogeneous neurodegenerative disorders in which there were overlapping appearances in the clinical phenotype.The partial SCA3/MJD1 patients may have only pure spastic paraplegia without ataxia,so genetic tests can suggest the clinical diagnosis of HSP especially with family history.