Screening for causative genes in unknown hemolytic anemia

α-血红蛋白稳定蛋白能与α-血红蛋白特异结合，防止其在红细胞中沉淀。AHSP作为分子伴侣在不稳定的游离α-珠蛋白单体的稳定过程中起着重要的作用，它会产生活性氧物种，导致红细胞蛋白质和脂质的损伤。为了验证AHSP基因缺陷可能是Heinz小体阳性贫血或感染或用药引发的急性溶血性贫血的原因，我们进行了一项病例对照研究，检测了28例溶血性贫血患者和95例对照的7个单核苷酸多态性(SNPs)，发现人类AHSP基因的某个单倍型与未知溶血性贫血的一个亚群有显著关联。该单倍型包括4个SNPs(-557G、-465T、-201G和+248A)和位于AHSP基因5‘侧翼区的缺失插入多态(DIP)T15，报告基因分析表明该单倍型约占对照单倍型转录活性的23%。体外诱变分析表明，SNP-201G和T15都是AHSP基因转录活性降低的原因。我们的结论是，AHSP基因与一组Heinz体阳性RBC或感染/药物诱导的溶血性贫血的疾病易感性有关，并且-201A/T15纯合子更容易受到氧化应激的影响。

Alpha-hemoglobin stabilizing protein (AHSP) binds specifically to α-hemoglobin, and prevents its precipitation in red blood cells (RBC). AHSP plays an important role as a molecular chaperone in the stabilization of unstable free α-globin monomer, which generates reactive oxygen species, resulting in damage to red cell protein and lipids. To examine that AHSP gene defects might account for either Heinz body-positive anemia or acute hemolytic anemia triggered by infection or drug administration, we performed a case-control study by examining seven SNPs (single nucleotide polymorphisms) of 28 hemolytic anemia patients and 95 controls, and found that a certain haplotype of the human AHSP gene had significant association with a subgroup of unknown hemolytic anemia. The haplotype included four SNPs (-557G,-465T,-201G and +248A) and a deletion-insertion polymorphism (DIP), T15, in 5'-flanking region of AHSP gene, and a reporter gene assay showed that the haplotype accounts for about 23% transcriptional activity of a control haplotype. In vitro mutagenesis analysis revealed that both the SNP-201G and T15 are responsible for decreased transcriptional activity of AHSP gene. We conclude that the AHSP gene is correlated to disease-susceptibility in a group of hemolytic anemia with either Heinz body-positive RBC or infection/drug-induced episodes, and that the homozygotes of-201A/T15 are more susceptible to oxidative stress.