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目的研究丙酮酸脱氢酶缺乏症发病分子遗传学机制,从基因水平诊断丙酮酸脱氢酶缺乏症,为遗传咨询和产前基因诊断提供依据。方法对临床表现及实验室检查符合丙酮酸脱氢酶缺乏症的1例患儿采用PCR法对PDHA1基因的11个外显子及外显子交界区进行扩增,并通过对扩增产物直接测序检测突变。采用生物信息学方法对新突变进行氨基酸保守型分析,预测蛋白二、三级结构,鉴定其致病性。结果先症者PDHA1基因第11外显子出现小片段重复突变,即c.1111_1158dup48bp,为新发突变。50例正常对照直接测序均未检测到c.1111_1158dup48bp突变。蛋白质二级、三级结构预测结果显示:新突变c.1111_1158dup48bp引起Ser371_Phe386的16个氨基酸重复,导致蛋白质二、三级结构发生明显变化,而正常对照无此变化。结论 PDHA1基因c.1111_1158dup48bp重复突变不是多态性变异,可能是一种新的致病性突变,导致丙酮酸脱氢酶缺乏症的发病。
Objective To study the molecular genetic mechanism of pyruvate dehydrogenase deficiency and to diagnose pyruvate dehydrogenase deficiency from the gene level to provide basis for genetic counseling and prenatal gene diagnosis. Methods A total of 11 exon and exon junctions of PDHA1 gene were amplified by polymerase chain reaction (PCR) in 1 patient with clinical manifestations and laboratory tests of pyruvate dehydrogenase deficiency. The amplification products were directly Sequencing detection of mutations. Amino acid conservative analysis of the new mutation was carried out by using bioinformatics methods to predict the secondary and tertiary structure of the protein and identify its pathogenicity. The results of first symptom PDHA1 gene exon 11 small fragments of repeated mutations, namely c.1111_1158dup48bp, as a new mutation. None of the 50 normal control direct sequencing detected c.1111_1158dup48bp mutation. The results of secondary and tertiary structure prediction of protein showed that the new mutation c.1111_1158dup48bp caused 16 amino acid repeats of Ser371_Phe386, resulting in significant changes in the secondary and tertiary structure of the protein, but no change in the normal control. Conclusion The repeat mutation of c.1111_1158dup48bp of PDHA1 gene is not a polymorphic mutation and may be a new pathogenic mutation, leading to the onset of pyruvate dehydrogenase deficiency.