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目的 探讨中国人结节性硬化症 (tuberoussclerosis complex,TSC)基因 (TSC1)外显子 4的基因突变特征及多态现象。方法 采用聚合酶链反应 -单链构象多态 (PCR- SSCP)技术结合 DNA测序对来源于 2 1个家系的 2 5例 TSC患者、2 3名父母及 6 0名正常对照进行了 TSC1基因外显子 4检测。结果 正常对照 SSCP均表现为一种相同的带型。在 2 5例 TSC患者中 ,有 1例散发型患者的 SSCP带型与正常对照不同 ,经 DNA测序证实该患者在 TSC1基因的外显子 4发生了 35 2 ins A杂合突变。在无症状的 2 3名父母中 ,有 1例患者的母亲亦检测到不同于正常的 SSCP带型 ,经测序证实发生了 34 7A→ C碱基改变 ,由于编码的氨基酸未改变 ,均为缬氨酸 (Val) ,考虑为一种多态现象。结论 35 2 ins A是一种新型插入突变 ,未呈热点分布。 34 7A→ C是一种罕见的新单核苷酸多态。
Objective To investigate the gene mutation and polymorphism of exon 4 in Chinese tuberous sclerosis complex (TSC) gene. Methods Twenty-five TSC patients, 23 parents and 60 healthy controls from 21 pedigrees were genotyped by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) combined with DNA sequencing. Exon 4 test. Results The normal control SSCP showed the same type. In 25 cases of TSC patients, one case of sporadic patients SSCP banding with normal control, DNA sequencing confirmed that the patient TSC1 gene exon 4 352 ins A heterozygous mutation. Among the 23 asymptomatic parents, one of the mothers also detected a different SSCP banding pattern from normal, confirming the 34 7A → C base change by sequencing. Since the encoded amino acids were unchanged, all were valines Val, considered as a polymorphism. Conclusion 35 2 ins A is a novel insertion mutation, not hotspot distribution. 34 7A → C is a rare new single nucleotide polymorphism.