A genetic and demographic study of hemophilia A in Brazil.

A genetic and demographic study was made of patients with hemophilia A in Rio Grande do Sul, Brazil, during a 15-year period. The study comprised 104 patients belonging to 70 pedigrees. Life expectancy at birth increased from 32.2 to 44.5 years, mean age of death from 11.1 to 14.6 years, and survival to maturity from 33 to 38%. However, fertility decreased from an average number of 1.6 to 0.8 children. Among the normal brothers, the average number of offspring was decreased from 2.2 to 1.5 children. The fitness of patients in this population, in spite of the increase of the average life expectancy, was decreased due to the decrease of fertility, from 0.47 to 0.43 using the normal brother as control, and from 0.35 to 0.20 using the general population as control.