遗传性α-地中海贫血的全球分布与疟疾暴露地区一致,[18]Flint J, Hill AV, Bowden DK, et al. High frequencies of alpha-thalassaemia are the result of natural selection by malaria. Nature. 1986;321:744-750.http://www.ncbi.nlm.nih.gov/pubmed/3713863?tool=bestpractice.com这提示α-地中海贫血对于严重疟疾感染具有保护作用。所以,α-地中海贫血常见于撒哈拉以南非洲、地中海盆地、中东、南亚以及东南亚,而且不同的遗传子型在这些地区中各自有不同的发生频率。[19]Bernini LF. Geographic distribution of alpha thalassemia. In: Steinberg M, Forget B, Higgs D, et al, eds. Disorders of hemoglobin. New York, NY: Cambridge University Press; 2001:878-894.[20]Weatherall DJ. The definition and epidemiology of non-transfusion-dependent thalassemia. Blood Rev. 2012;26(suppl 1):S3-S6.http://www.ncbi.nlm.nih.gov/pubmed/22631040?tool=bestpractice.com
α(0) 变异体较为重要,因为它可导致 Hb H 症和 Hb Bart 胎儿水肿综合征,且最常见于东南亚,其中,在泰国北部的携带者比例可达 14%,而在中国南方为 5% 至 8.8%。[13]Chui DH, Waye JS. Hydrops fetalis caused by alpha-thalassemia: an emerging health care problem. Blood. 1998;91:2213-2222.http://www.ncbi.nlm.nih.gov/pubmed/9516118?tool=bestpractice.com
非缺失性突变 Hb 康斯坦特斯普瑞在东南亚地区也较为常见。[19]Bernini LF. Geographic distribution of alpha thalassemia. In: Steinberg M, Forget B, Higgs D, et al, eds. Disorders of hemoglobin. New York, NY: Cambridge University Press; 2001:878-894.
α-地中海贫血在美国的流行病学特征反映了全球分布模式。美国最常见的α(+) 地中海贫血类型是由α(3.7) 缺失(即单个α-珠蛋白基因缺失)所致,见于约 30% 的非洲裔美国人中。[21]Beutler E, West C. Hematologic differences between African-Americans and whites: the roles of iron deficiency and alpha-thalassemia on hemoglobin levels and mean corpuscular volume. Blood. 2005;106:740-745.http://bloodjournal.hematologylibrary.org/cgi/content/full/106/2/740http://www.ncbi.nlm.nih.gov/pubmed/15790781?tool=bestpractice.com然而,即使在纯合子状态下,此种疾病也将只会引起轻度小红细胞贫血症。较严重的 Hb H 和 Hb Bart 胎儿水肿综合征临床疾病常见于美国西部(尽管如今在美国各地都有发现),并且由于过去 20 年亚洲移民的增加,此症的患病率呈现出显著增加趋势。[10]Vichinsky EP, MacKlin EA, Waye JS, et al. Changes in the epidemiology of thalassemia in North America: a new minority disease. Pediatrics. 2005;116:e818-e825.http://pediatrics.aappublications.org/cgi/content/full/116/6/e818http://www.ncbi.nlm.nih.gov/pubmed/16291734?tool=bestpractice.com