Congenital factor XIII deficiency in Switzerland: from the worldwide first case in 1960 to its molecular characterisation in 2005.

Coagulation factor XIII (FXIII) has a major role in the final stage of blood coagulation, is important for wound healing and maintaining pregnancy. Severe congenital FXIII deficiency is a rare disorder with 1 patient in 1-3 million. Untreated, it causes bleeding events, with intracranial haemorrhage being the major cause of death, impaired wound healing, and abortion. FXIII deficiency was traditionally diagnosed using the clot solubility test, but quantitative FXIII activity and antigen assays are preferred today. Treatment consists of replacement therapy with FXIII concentrates administered every 4-6 weeks. The molecular-genetic causes of FXIII deficiency are mutations in the genes coding for the FXIII A- and B-subunits. More than 60 mutations distributed throughout the FXIII A-subunit gene have been identified so far and 4 mutations in the FXIII B-subunit gene. The first case of congenital FXIII deficiency was reported in Switzerland in 1960. In Switzerland we observed a disproportionately high incidence, which can be explained in part by a founder effect. In this article, we summarise general facts on severe congenital FXIII deficiency, and we characterise all FXIII deficient patients living in Switzerland, including the first case described in 1960 who is a member of a large family originating from the canton of Uri