A 型先天性血友病的发病率在男性中约为 1/5000,而 B 型先天性血友病男性中为 1/30,000。[3]Soucie JM, Evatt B, Jackson D; the Hemophilia Surveillance System Project Investigators. Occurrence of hemophilia in the United States. Am J Hematol. 1998;59:288-294.http://www3.interscience.wiley.com/cgi-bin/fulltext/5005943/PDFSTARThttp://www.ncbi.nlm.nih.gov/pubmed/9840909?tool=bestpractice.com在美国,每年约有 400 名婴儿出生时患有血友病,先天性血友病的男性发病率估计为 18,000 人,且大多数归为重度病例。[4]National Heart, Lung and Blood Institute. What is hemophilia? July 2013. http://www.nhlbi.nih.gov (last accessed 16 March 2017).http://www.nhlbi.nih.gov/health/dci/Diseases/hemophilia/hemophilia_what.html在英国,血友病学会预计约 6000 人患有血友病。The Haemophilia Society先天性血友病影响所有种族,因此在全世界范围均有分布。[5]World Federation of Hemophilia. Report on the annual global survey, 2009. 2011. http://www.wfh.org (last accessed 16 March 2017).http://www1.wfh.org/publications/files/pdf-1428.pdf其遗传模式为 X-连锁模式。[6]Pruthi RK. Hemophilia: a practical approach to genetic testing. Mayo Clin Proc. 2005;80:1485-1499.http://www.ncbi.nlm.nih.gov/pubmed/16295028?tool=bestpractice.com因此,几乎只有男孩和/或男性患病,但也有很多女性携带者(大约 30%)的凝血因子水平由于莱昂化作用(正常 X 染色体的随机失活)处于血友病范围内,可能有需要适当处理的出血症状。由于极度莱昂化作用、纯合性、镶嵌现象或 Turner 综合征,已有女孩和/或女性罹患重度血友病的罕见病例的描述。获得性血友病较罕见,获得性 A 型血友病的发病率为每年每百万人口 1.48 例。[7]Collins PW, Hirsch S, Baglin TP, et al. Acquired hemophilia A in the United Kingdom: a 2-year national surveillance study by the United Kingdom Haemophilia Centre Doctors' Organisation. Blood. 2007;109:1870-1877.http://bloodjournal.hematologylibrary.org/cgi/content/full/109/5/1870http://www.ncbi.nlm.nih.gov/pubmed/17047148?tool=bestpractice.com
有关获得性血友病,在每百万人口中约有 1 至 3 人患病。男女均同样受到影响。与常见的遗血友病一样,其在全世界范围内的所有种族中出现。