G6PD缺乏症酶学诊断与多重SNaPshot基因诊断的比较

Comparison of detection of glucose-6-phosphate dehydrogenase deficiency by enzymatic diagnosis and the multiplex SNaPshot genetic diagnosis

目的了解葡萄糖-6-磷酸脱氢酶(glucose-6-phosphate dehydrogenase,G6PD)缺乏症酶学诊断与基因诊断检出情况,并对这两种方法学进行分析比较。方法通过G6PD/6-磷酸葡萄糖酸脱氢酶(6-phosphogluconate dehydro-genase,6PGD)比值法和多重SNa Pshot基因诊断技术对168例血样进行G6PD缺乏症酶学诊断和基因型诊断,分析各自的检出情况,比较比值法和多重SNa Pshot法的结果,并以测序结果为金标准对两种方法进行方法学评价。结果酶学诊断阳性率为4.76%。基因诊断突变率为22.02%,以c.[1311C>T(;)1365-13T>C]同义突变最常见(72.97%),错义突变率为5.35%。错义突变标本的G6PD/6PGD比值较同义突变及未检出突变低,差异有统计学意义(P<0.05);而同义突变与未检出突变间G6PD/6PGD比值无统计学差异(P>0.05)。多重SNa Pshot法基因分型结果均与DNA直接测序分析的结果完全一致。比值法无法检出同义突变,且漏检一例错义突变杂合子,其筛查错义突变的灵敏度和特异度分别是88.89%和100.00%。结论 G6PD/6PGD比值法虽可较有效地筛查错义突变但不能检出同义突变和全部的女性杂合子,而多重SNaPshot基因分型方法可有效检出多种G6PD基因突变类型。

Objective To compare the dectection result of glucose-6-phosphate dehydrogenase（G6PD） deficiency byenzymatic diagnosis and genetic diagnosis. Methods Both enzymatic diagnosis and genetic diagnosis were performed on 168 cases of blood samples by the G6PD/6-phosphogluconate dehydrogenase（6PGD） ratio test and the multiplex SNa Pshot geneticdiagnosis assay respectively. The typing results of G6PD/6PGD ratio test and multiplex SNa Pshot assay were analyzed andcompared. Furthermore, methodological evaluations of these two methods were performed based on the golden standard ofsequencing results. Results The positive rate of enzymatic diagnosis was 4.76%,while the mutation rate of genetic diagnosiswas 22.02%. Synonymous mutation of c.[1311C〉T（;）1365- 13T〉C] was the most common mutation（72.97%）. The rate ofmissense mutation was 5.35%. The G6PD/6PGD ratio of missense mutation specimens was significantly lower than that ofsynonymous mutation and of non-detected mutation（P〈0.05）. Whereas, there was no significant differences in the G6PD/6PGD ratio between synonymous mutation and non- detected mutation（P〉0.05）. All the genotyping results of multiplexSNa Pshot assay were in complete concordance with the direct DNA sequencing. The ratio test cannot detect synonymousmutation. As one case of missense mutational heterozygote was not be detected by the ratio test, the sensitivity and specificity ofthis method for screening out missense mutation were 88.89% and 100.00% respectively. Conclusion Although G6PD/6PGD ratio test is a relative effective way of screening missense mutation, it could not detect synonymous mutation and all thefemale heterozygous carriers. Whereas, multiplex SNa Pshot genotyping assay can detect various G6 PD mutational types.