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目的 分析我国典型的 Rett综合征患儿甲基化 Cp G结合蛋白 - 2基因 (methyl- Cp G- bindingprotein2 ,MECP2 )突变。方法 使用 PCR扩增、单链构象多态性分析、PCR产物克隆和 DNA测序的方法 ,检测分析了 2 6例 Rett综合征患儿、其父母和其中 2例患儿的妹妹 MECP2基因 3个外显子的基因突变。结果 2 6例 Rett综合征患儿中发现 14例有 9种类型 MECP2基因的杂合性突变 ,突变均位于第 3外显子。其中 7例有 3种错义突变 :C4 73T(T15 8M) 4例 ,C6 74 G(P2 2 5 R) 1例 ,C916 T(R30 6 C) 2例 ;4例有 3种无义突变 :C5 0 2 T(R16 8X) 2例 ,C76 3T(R2 5 5 X) 1例 ,C880 T(R2 94 X) 1例 ;2种由于缺失导致的移码突变 :1例为 115 2 del4 4 bp和 1例 115 8- 116 7/ 1171- 1186 del2 6 bp;1种由于碱基插入导致的移码突变 :874 ins A。 115 8- 116 7/ 1171- 1186 del2 6 bp和 874 ins A突变为首次报告。突变均为新生突变。此外 ,新发现了一种源于父亲的错义变异 C114 1G(P381A)。结论 我国 Rett综合征患儿存在 MECP2基因突变。典型的Rett综合征 MECP2基因突变率大于 5 0 %。
Objective To analyze the mutation of methyl-Cp G-binding protein 2 (MECP2) in children with Rett syndrome. Methods PCR amplification, single strand conformation polymorphism analysis, PCR product cloning and DNA sequencing were used to detect and analyze 26 cases of Rett syndrome. The parents and 2 of them had sister MECP2 gene 3 Exon gene mutations. Results There were 14 heterozygous mutations of 9 types of MECP2 genes found in 26 children with Rett syndrome, all of which were located in exon 3. There were 3 kinds of missense mutations in 7 cases: C473T (T15 8M) in 4 cases, C6 74G (P225R) in 1 case and C916T (R306C) in 2 cases. There were 3 nonsense mutations in 4 cases: 2 cases of C5 0 2 T (R16 8X), 1 case of C76 3T (R2 5 5 X) and 1 case of C880 T (R2 94 X). There were two kinds of frameshift mutations due to deletion: one case was 115 2 del4 4 bp And 1 case of 115 8- 116 7 / 1171-1166 del2 6 bp; a frameshift mutation due to base insertion: 874 ins A. 115 8- 116 7 / 1171- 1186 del2 6 bp and 874 ins A mutations were first reported. Mutations are neonatal mutations. In addition, a new missense mutation C114 1G (P381A) derived from the father was discovered. Conclusion There is MECP2 mutation in children with Rett syndrome in China. Typical Rett syndrome MECP2 gene mutation rate greater than 50%.