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目的 确定常染色体隐性遗传性聋 GJB2基因突变的类型和频率 ,从分子水平探讨发病机理。方法 收集中国人常染色体隐性遗传性聋 4个家系 (3 9名个体 )和健康对照组 50人的外周血 DNA样本。PCR扩增 GJB2基因片段 ,行 Apa 酶切和序列分析。结果 检出 2个家系 4例患者 GJB2基因2 3 5del C纯合性缺失 ,导致移码突变 ,2例患者为 2 3 5del C和 2 3 2 G→ A(Ala78Thr)双重杂合性突变。正常对照组中发现 1例 2 3 5del C携带者。耳聋患者组和健康对照组中均存在 79G→ A(V2 7I) ,3 4 1A→ G(E114 G)两种改变。在对照组中这两种改变的等位基因频率分别为 3 0 %、2 1%。结论 两个家系与 GJB2基因2 3 5del C有关 ,2 3 2 G→ A是 1个新的突变。
Objective To determine the type and frequency of GJB2 gene mutations in autosomal recessive hereditary deafness and to explore the pathogenesis from the molecular level. Methods Peripheral blood DNA samples from 4 Chinese families with autosomal recessive hereditary dementia (39 individuals) and healthy controls were collected. GJB2 gene fragment was amplified by PCR, Apa digestion and sequence analysis. Results The homozygous deletion of 23 5del C of GJB2 gene was detected in 4 of the 2 pedigrees, resulting in a frameshift mutation. The two patients were heterozygous mutations of 23 5del C and 2 3 2 G → A (Ala78Thr). One case of 2 3 5del C carriers was found in the normal control group. There were 79G → A (V2 7I) and 34A → G (E114G) changes in both deafness group and healthy control group. In the control group, the allele frequencies of these two changes were 30% and 21%, respectively. Conclusion The two families are related to GJB2 gene 2 3 5del C, and 2 3 2 G → A is a new mutation.