推荐回答（2个）
是由于基因不是正常基因不能翻译成正常功能性的红细胞或造血功能相关的蛋白质而产生的贫血。
比如镰状细胞性贫血（crescent cell anaemia，sickle-cell anemia）是一种遗传性血液病。如果夫妇双方都是镰状细胞性贫血基因的携带者，他们的子女就会有25％的可能是重型镰状细胞性贫血，50％的可能是轻型镰状细胞性贫血。目前全球有5000万人面临镰状细胞性贫血威胁。仅非洲每年就有30万新生儿是镰状细胞性贫血基因的携带者，其中50％不到5岁就夭折了。
镰状细胞贫血由β链基因点突变引起，珠蛋白的β基因发生单一碱基突变。正常β基因的第6位密码子为GAG,编码谷氨酸,突变后为GTG,编码缬氨酸,使成为HbS.在纯合子状态,当形成HbS后,HbS在脱氧状态下聚集成多聚体,因形成的多聚体排列方向与膜平行,与细胞膜的接触
[镰状细胞性贫血]
镰状细胞性贫血
又非常紧密,所以当多聚体达到一定量时,细胞膜便由正常的双凹形盘状变成镰刀形.该细胞僵硬,变形性差,易破而溶血,造成血管阻塞,组织缺氧,损伤,坏死。
若孩子从父母双方各遗传得到一个异常基因，那么他就会发生镰状细胞性贫血。但如果孩子只从双亲的一方遗传到一个异常基因，则他会带有镰状细胞性贫血的特质，即虽不会出现症状，但会把异常基因遗传给下代。
又比如 遗传性铁粒幼细胞贫血的致病基因
铁粒幼细胞贫血（SA）包括一组铁利用障碍所致的贫血性疾病，患者由于骨髓红细胞系统生成障碍，出现程度不等的贫血，血清铁升高，骨髓出现大量铁颗粒围绕在细胞核周围的环形铁粒幼细胞。SA可分为获得性和遗传性两大类，获得性包括原发性SA和继发性SA，原发性SA较常见的是骨髓增生异常综合征（MDS）中的难治性贫血伴环形铁粒幼细胞（RAS），继发性SA 主要是治疗肿瘤或者结核中化疗药物造成的骨髓损害。遗传性SA主要为X连锁铁粒幼细胞贫血（XLSA）。最近认识到XLSA是由于红细胞系统特异性δ氨基γ酮戊酸合成酶 2（ALAS 2）基因突变所致，ALAS2基因定位在X染色体上，并已获得克隆，为采用基因治疗的方法提供了可能性。XLSA是一种酶缺陷病，而 MDS是干细胞缺陷所致的克隆性疾病，诊断标准和治疗措施都有很大区别，有必要进行深入细致的鉴别分析。
就是说，这种贫血的症状是由基因决定的，可能是镰刀型细胞贫血症，如果是这种病，患者的红细胞性状会像镰刀一样，而正常人的是圆饼状，所以患者红细胞运输氧等物质的功能低于正常人，自然贫血。
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