Factor XI deficiency in the French Basque Country

Thirty-nine patients with factor XI deficiency were diagnosed in our genera l hospital, which serves all the French Basque Country (about 290 000 inhab itants), between 1985 and 1995. Biological and clinical data of these cases are reported herein. Factor XI deficiency seems significantly more frequen t in Basques than in the other non-Ashkenazi populations. Molecular studies should be performed for typing these cases in the view of population genet ics.