In the study conducted by Mannucci et al. in the years 2010 and 2014, 251 children with severe haemophilia A under 6 years of age, without inhibitors and minimally treated by less than five exposures to FVIII, from 42 centres in 14 countries (India, Egypt, Iran, United States Italy, and others) participated. Here, F8 is linked to hemophilia A.