罕见的2例A307亚型的分子生物学研究

Study on Molecular Biology of Rare Two A307 Phenotypes

目的:对2例血清学定型困难的血液标本进行ABO基因检测,探讨其分子遗传学基础。方法:应用PCRSSP方法对此2例血清学定型困难的标本进行ABO基因分型,并对其ABO基因第6、7外显子扩增后进行直接测序和克隆测序,从而确定其基因型。结果:2例标本血清学表现为红细胞与抗-A 1+凝集,与抗-A1不凝集,在血清中存在抗-A1;PCR-SSP基因分型显示为A/O1;直接测序和克隆测序显示,此2例标本A等位基因在第7外显子存在nt467C>T及nt745C>T突变,导致第156位密码子编码的氨基酸由脯氨酸(Pro)变为亮氨酸(Leu),第249位密码子编码的氨基酸由精氨酸(Arg)变为色氨酸(Trp)。结论:血清学和基因测序结果表明,此2例标本为罕见的A307亚型。

Objective: To identify the genotypes of the 2 blood samples w hose serological typing w ere difficult by DNA sequencing analysis,and to investigate the molecular genetic basis of their genotypes. Methods: The 2 blood samples w ere preliminary genotyped by PCR- SSP. The complete exon 6 and 7 in the ABO genes w ere amplified by PCR and the PCR products w ere directly sequenced and clonal sequenced in order to identify the genotypes. Results: The forw ard typing show ed that both samples w ere w eak A,w hile the reverse typing show ed that the samples contained anti-A1. They w ere preliminarily genotyped as A / O1. Results: The sequencing analysis show ed that the 2 samples contained the nt467 C > T and nt745 C > T mutation in the A allele,w hich resulted in an amino acid change from Proline( Pro) to Leucine( Leu) at codon 156 and also from Arginine( Arg) to Tryptophan( Trp) at codon 249. Conclusion: Through serology results and sequencing analysis,the 2 samples are identified as rare A307 phenotypes.