发作性运动诱发性运动障碍一家系致病基因定位与突变分析

摘要

Objective To study the clinical characteristics and genetic cause of a Chinese family affected with paroxysmal kinesigenic dystonia(PKD).Methods The detailed clinical data and the blood samples of the affected patients with PKD and their relatives were collected.After genomic DNA was extracted from blood leukocytes,target linkage analysis Was performed using multiplex PCR by microsatellite marker's located in the reported critical region on chromosome 16.All exons and flanking regions of SCNN1G and ITGAL genes were amplified by PCR-sequence.Results In this three-generation 12 member family,5 individuals have been diagnosed as PKD.Target linkage analysis suggested the disease gene linked to chromosome 16.between D16S3396 and D16S3057 with two-point LOD score of 1.47 at recombination fraction(θ)=0.0.All affected individuals shared a common haplotype which co-segregated with the phenotype.Except for 8 reported SNPs,no pathologic sequence variants were found in candidate genes SCNN1G and ITGAL.Conclusions The studied family is genetically linked to the reported critical locus of PKD on chromosome 16.SCNN1G and ITGAL were ruled out as the causative genes for the studied pedigree.Further genetic analysis in this family may reveal new genetic cause responsible for PKD.%目的 探讨发作性运动诱发性运动障碍(PKD)家系临床特点,定位致病基因和检测突变.方法 对1个PKD家系的患者及其亲属进行临床资料分析,采集外周静脉血标本提取基因组DNA.选取16号染色体目前已报道位点内的微卫星标记,采用多重PCR技术对该家系进行连锁分析;普通PCR方法扩增候选基因SCNN1G和ITGAL外显子及毗邻序列,进行测序及家系共分离检测.结果 该家系3代12人,共5例患者.连锁分析提示当重组率(0)为0.0时在D16S3396和D16S3057处取得最大两点LOD值1.47,支持连锁.所有患者均携带完全相同的单体型并与疾病表型共分离.ITGAL、SCNN1G测序共发现8个序列变异,但均为已报道的单核苷酸多态(SNP),未发现家系共分离的致病性突变.结论 该PKD家系致病基因与位于16号染色体上已报道的PKD遗传位点连锁,进一步证明其为PKD的重要遗传位点;基本排除SCNN1G和ITGAL为该家系的致病基因,其致病基因有待进一步探索.