In persons with congenital FXII deficiency the condition is lifelong. People affected may want to alert other family members as they may also carry the gene. A 1994 study of 300 healthy blood donors found that 7 persons (2.3%) had FXII deficiencies with one subject having no detectable FXII (0.3%). This study is at variance with estimates that only 1 in 1,000,000 people has the condition.
