Characteristics Of Mutation Of Disease-causing Genes In Chinese Patients Diagnosed As Hereditary Spastic Paraplegia And Its Relation To Clinical Phenotype

ObjectivesTo detect the mutations of spastin,atlastin,NIPA1 and REEP1 Gene in Chinese patients with hereditary spastic paraplegia(HSP) and establish the base of the gene diagnosis of HSP.To screen the MJD gene changes for the patients above and ascertain the spastic paraplegia subtype of MJD.MethodsMutation analysis of spastin,atlastin and NIPA1 gene,carried out by polymerase chain reaction and DHPLC combined with sequencing in 56 unrelated HSP individuals consisting of the indexes from 24 HSP families and 32 sporadic cases.Then spastin, atlastin and NIPA1 genes of these 24 indexes,while REEP1 gene of all 56 individuals were screened by polymerase chain reaction combined with direct sequencing.MJD gene of individuals above were segregated by means of Agrose Gel Electrophoresis as well as Polyacrylamide Gel Electrophoresis after polymerase chain reaction proceeded, and then Changes of them detected were confirmed by sequencing.ResultsOne novel mutation of the spastin gene was identified(1616+1g＞t) in one autosomal dominant family;no disease causing mutation of the atlastin gene was detected in all cases;A reported mutation of the NIPA1 gene(c.316G＞A) was identified in an autosomal dominant family;no mutation was identified in REEP1 gene of all cases.8 polymorphisms in the spastin gene,10 polymorphisms in the atlastin gene,1 polymorphism in the NIPA1 gene and 5 polymorphisms in the REEP1 gene were identified.Conclusions(1) The mutation of spastin gene,1616+1g→t,have not been reported previously in the world. (2) The mutation of atlastin gene in Chinese HSP patients may be rare.The lower mutation rate may be correlated with racial diferentation.(3) We identified c.316G＞A,a mutation of NIPA1 gene in an autosomal dominant HSP family,which is a hotspot.(4) The REEP1 gene were first screened in Chinese patients,mutations of which may be rare.(5) We also found a lot of polymorphisms in the four genes.Polymorphisms are common in HSP patients,but mutations are less in the four genes.We should detect other genes of HSP.(6) We found changes of the MJD gene occure in 4 previously diagnosed HSP families, suggesting the importance of gene screening.(7) DHPLC together with DNA sequencing is an efficient and economical method for screening mutations.