SERPINC1 and Rare hereditary thrombophilia: In this study, the cosegregation in cis of the two defects (i.e., F5, c.1691G>A; SERPINC1, c.1171C>T) leads to the highest penetrance of familial thrombophilia and could be rarely terminated by recombinant events because of their relative short distance (g.169.549.811 and g.173.907.497 respectively).