In conclusion, we found an increasing prevalence of sporadic haemophilia A in severe and moderately severe patients with haemophilia A in recent decades. Haemophilia A is an inherited bleeding disorder caused by mutations in the gene encoding clotting factor (F) VIII ( I F8 i ).[1] Mutations in I F8 i are mainly transmitted by heterozygous mothers (carriers) who are usually asymptomatic. HA, haemophilia A; n, number gl Our results corroborate with the study of Kasper et al., who analysed 804 haemophilia pedigrees, and found that familial haemophilia accounted for 45% of the cases in patients with severe haemophilia A, and 70% of the cases in mild to moderate haemophilia A or B.[[2], [8]] A chinese study aimed at identifying the source of mutations in 393 Chinese families with sporadic haemophilia A revealed that most mothers of these sporadic patients were carriers. [Extracted from the article]