When genetic and surname analyses meet historical sources: The C56R mutation associated with factor XI deficiency as a marker of human migration during the Spanish Reconquista.

The C56R mutation associated with factor XI deficiency has been first evidenced in individuals from the French Basque Country. Genetic investigations revealed that this mutation occurred about 5400 years ago as a founder effect in this zone. Other cases were subsequently described in Southwestern Europe. Noticeably a cluster of cases was evidenced in Yecla, a small city from the province of Murcia, in Southeastern Spain. In correlation with historical sources our genetic data and surname analysis argue for associating this mutation with the migration of people from Western Pyrenees (and more probably from the Navarra province) toward Southeastern Spain during the Reconquista period.