RHD基因101A＞G和845G＞A突变导致Rh弱D的分子机制

摘要

目的 探讨1例罕见的Rh弱D型个体的分子机制.方法 采用常规血清学方法和间接抗球蛋白方法(indirect antiglobulin test,IAT),确认样本RhD血型.应用聚合酶链反应(polymerase chain reaction,PCR)、逆转录-聚合酶链反应(reverse transcription-polymerase chain reaction,RT-PCR)和DNA序列分析等方法对先证者RHD基因转录调控序列和全编码序列进行突变筛选和检测.对cDNA扩增产物进行TA克隆和单倍型分析.结果 先证者RhD血清学检测为弱阳性;PCR扩增实验表明先证者存在RHD基因的第1～10外显子,gDNA和cDNA直接测序101位A/G和845A/G杂合.TA克隆得出两个单倍型,即101A＞G突变(RHD弱D 101G)和845A＞G突变(RHD弱D type 15).结论 第101A＞G突变和845A＞G突变导致先证者红细胞D抗原表达减弱,因而表现为弱D型.%Objective To explore the molecular basis for an individual with a rare weak D phenotype.Methods Regular serological assaying and indirect antiglobulin testing (IAT) were performed to characterize the RhD blood group.Mutations of the RHD gene were screened by polymerase chain reaction (PCR), reverse transcription PCR and DNA sequencing.Amplified cDNA product was TA cloned and subjected to haplotype analysis.Results The RhD blood group of the proband was determined as weak D.The result of PCR amplification showed that all of the 10 exons of the RHD gene were present.Heterozygote status of 101A/G and 845A/G were determined by gDNA and cDNA sequencing.After TA cloning and haplotype sequencing, two alleles 101A＞G mutation (weak D 101G) and 845G＞A mutation (weak D type 15) were revealed.Conclusion 101A＞G and 845G＞A mutations are responsible for the low expression of RhD antigen on the red blood cells of the proband, which has resulted in a weak D phenotype.