人类β类珠蛋白基因的排列为5’-ψβ_2-(?)-Gγ-Aγ-ψβ_1-δ-β-3’(ψβ_1和ψβ_2为假基因),全长约65kb。β类珠蛋白基因具有遗传异质性.在正常情况下,某些核苷酸位点可以发生中性改变,构成β类珠蛋白基因多态性。此种多态性对β珠蛋白的合成并不产生影响,只是作为一种遗传标志而已。β地中海贫血(以下简写为β地贫或β~(thal))除了β珠蛋白基因(简写为β基因)的外显子、内含子或旁侧序列发生特异性突变或部分缺失(它 The sequence of human β-globin gene is 5’-ψβ_2 - (?) - Gγ-Aγ-ψβ_1 -δ-β-3 ’(ψβ_1 and ψβ_2 are pseudogenes) with a total length of about 65kb. The β-globin gene has genetic heterogeneity, and under normal circumstances some nucleotide sites may undergo a neutral change to form a β-globin gene polymorphism. This polymorphism does not affect the synthesis of β-globin, but only as a genetic marker only. Beta thalassemia (hereinafter referred to as beta thalassemia or thal) Exon, intron or flanking sequences of the beta globin gene (abbreviated as beta gene) are specifically mutated or partially deleted