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目的研究Hunter综合征患者的艾杜糖-2-硫酸酯酶(iduronate-2-sulfatase,IDS)基因的突变情况,为产前基因诊断等打下基础。方法应用尿粘多糖含量检测、聚合酶链反应-变性高效液相色谱(poly-merase chain reaction-denaturing high-performance liquid chromatography,PCR-DHPLC)分析对1例Hunter综合征患者及其父母的IDS基因的突变热点第9、3、8外显子进行突变检测,并对PCR-DHPLC检出的突变样品进行直接测序。结果经PCR-DHPLC分析发现该患者的IDS基因第9外显子有明显异常峰形;DNA序列分析进一步发现该外显子发生一新的移码突变,突变部位在第482位密码子(TTA)内,即cDNA第1569bp的T后插入了2个T,致使新肽链提前在第483位遇上终止密码TAA,导致新肽链从原来的550个氨基酸缩短至482个。该患儿为这一突变的半合子,而其母为这一突变的杂合子。结论PCR-DHPLC和DNA序列分析是诊断Hunter综合征的有效方法,发现的移码突变(1569+TT)导致肽链比正常的少了68个氨基酸,从而引起IDS酶活性明显降低,可能是该Hunter综合征患者的致病原因。
Objective To study the mutation of iduronate-2-sulfatase (IDS) gene in Hunter syndrome and lay a foundation for the diagnosis of prenatal gene. Methods The urine of IDS gene in patients with Hunter’s syndrome and its parents was detected by polyglycolide and poly-merase chain reaction-denaturing high-performance liquid chromatography (PCR-DHPLC) Mutation hot spots 9,3,8 exons mutation detection, and PCR-DHPLC mutation samples were directly sequenced. The results of PCR-DHPLC analysis found that the patient IDS gene exon 9 was significantly abnormal peak; DNA sequence analysis further found that the exon a new frameshift mutation in the mutation site in the 482 codon (TTA ), That is, insertion of two T’s after the 1569 bp of cDNA resulted in the termination of the new peptide sequence at the 483th stop codon TAA, resulting in the shortening of the new peptide chain from the original 550 amino acids to 482 amino acids. The child is the mutant hemizygous child whose mother is the mutant heterozygote. Conclusion PCR-DHPLC and DNA sequence analysis are effective methods for the diagnosis of Hunter’s syndrome. The found frameshift mutation (1569 + TT) leads to a 68-amino acid decrease in the peptide chain compared with normal, leading to a significant decrease in IDS enzyme activity, Hunter syndrome causes of the disease.