In European nations the carrier rate varies, for example in Sweden an estimated 1 in 44 persons are carriers, while in Northern Ireland the rate is estimated at 1 in 20. Retroactive testing of donors with new DNA testing procedures for cystic fibrosis would indicate the incidence of carriers in the donor population and its relevance for children subsequently born from carrier donors. Present standards recommend a 6 month quarantine period and HIV-1 antibody retest before frozen human semen donor specimens are released for use. The purpose of this study was to determine the incidence of cystic fibrosis carriers in a large semen donor population being used for infertility treatment and to identify any seronegative donors infected with HIV-1. This is similar to the estimated 1 in 25 incidence of CF carriers in the American caucasian population.
Cystic fibrosis is the most common recessive disease in the caucasian population.
DNA testing of semen donors will reduce the chance that a donor carries CF from 1 in 25 to 1 in 161, accomplishing almost a 7 fold reduction in CF risk for offspring from tested semen donors. The chance that an individual with no family history of CF who uses a DNA tested donor will bear a child with CF is reduced to approximately 1 in 16,100. These results demonstrate that genetic screening for CF is an important factor in a gamete donor bank and that CF screening of donors is a responsible policy that will eliminate most high risk carriers. With regard to HIV-1, it is likely that the intense screening procedure for high risk individuals is partially responsible for preventing the occurrence of HIV transmission among donors. None of our donors had HIV detected by PCR nor seroconverted during the donation period.