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作者报导2例Gunther氏病(先天性红细胞生成性卟啉病CEP)患者中6′-氢尿卟啉Ⅲ合成酶(UROⅢ-S)活性特有缺陷的分子异常,第1例患者用多聚酶链反应技术特异扩增互补DNA,随之获得克隆和排列序列,其中对8个克隆进行了完全序列分析。与正常对照cDNA顺序比较,显示共存2类不同的点突变;6个克隆中第217核苷酸位点有T→C突变。导致蛋白质肽链上第73位点Cys→Arg替换,引进一个Mae Ⅱ限制性位点(5′-ACGT-3′);另2个克隆中第158核背酸位点C→T突变,导致蛋白质上第53位点Pro-Leu替换,且抑制了FokⅠ限制性位点(5′-GGATG[13N]-3′)。一些独立克隆未发现其它碱基改变的事实强烈显示2类不同的点突变存在于患者mRNA中。另外发现患者父母的
The authors report a molecular abnormality specific to the activity of 6’-uroporphyrin Ⅲ synthetase (UROⅢ-S) in 2 patients with Gunther’s disease (CEP) and the first patient with polymerase chain reaction The technique specifically amplifies complementary DNA, followed by cloning and alignment sequences, of which eight clones were fully sequenced. Compared with the normal control cDNA sequence, there were two kinds of point mutations that co-existed. The T-C mutation was found in the 217th nucleotide of the 6 clones. Resulting in the substitution of Cys-> Arg at position 73 of the protein peptide chain, introducing a Mae II restriction site (5’-ACGT-3 ’); mutation of the 158th nucleus dorsal acid site C → T in the other two resulted in Pro-Leu at position 53 on the protein was replaced and the Fok I restriction site (5’-GGATG [13N] -3 ’) was inhibited. The fact that some independent clones did not find any other base changes strongly suggested that two different types of point mutations were present in the patient’s mRNA. In addition to find the patient’s parents