在血红蛋白合成的遗传性疾病中,以成年期胎儿血红蛋白(HbF)增加为特征的那些疾病,在帮助我们了解红细胞内珠蛋白基因表现的调控方面具有很大的重要性。在这些疾病中,δβ-地中海贫血和遗传性胎儿血红蛋白持续症(Hereditary persistence of fetal haemo-globin,HPFH)在杂合子状况下就可有 HbF的增加,它们与其它一些伴有 HbF 增高的遗传性疾病如β-地中海贫血、镰状细胞性贫血等不同,后者在杂合子时 HbF 仅轻微升高。其纯合子的 HbF 升高可能是一种继发效应,而不是原发性遗传性缺陷的直接结果。HbF 通常包括两种类型γ链的混合物,它们的不同仅仅是在136位上是甘氨酸(Gγ)还是丙氨酸(Aγ)。Gγ和 Aγ链是不同基因的产物,这些基因与调控 HbA 和 HbA_2之β和δ链的基因以 GγAγδβ的顺序相环联。已经报告了各种类型的δβ-地中海贫血和 HPFH,它们在HbF 产生量和两种类型γ链的相对比例上不同。近来用溶液杂交和核酸内切限制酶图象的方法分析了 HPFH 或δβ-地中海贫血患者的DNA,发现某些这类疾病是由于珠蛋白基因 Among inherited disorders of hemoglobin synthesis, those characterized by an increase in fetal hemoglobin (HbF) in adulthood are of great importance in helping us to understand the regulation of erythrocyte globin gene expression. Among these diseases, there is an increase in HbF in heterozygous cases of δβ-thalassemia and hereditary persistence of fetal haemo-globin (HPFH), which is associated with increased hereditary HbF Diseases such as beta-thalassemia, sickle-cell anemia and the like differ only slightly in the heterozygous HbF. Homozygous HbF may be a secondary effect, rather than a direct result of primary genetic defects. HbF typically includes a mixture of two types of gamma chains, differing only whether glycine (G [gamma]) or alanine (A [gamma]) at position 136. Gγ and Aγ chains are the products of different genes that are cyclized in the order of GγAγδβ with genes that regulate the β and δ chains of HbA and HbA_2. Various types of [delta] [beta] -thalassemia and HPFH have been reported that differ in the amount of HbF produced and the relative proportions of the two types of [gamma] -chains. Recently, DNA from HPFH or delta-beta-thalassemia patients has been analyzed by solution hybridization and endonuclease restriction mapping and some of these diseases have been found to be due to globin genes