Pedigree of the AT-deficient family. Plasma AT levels are indicated (nd indicates not determined). The proband, indicated by the arrow, had a severe type II AT deficiency and was homozygous for the 7396T>C mutation. Individuals heterozygous for the factor V Leiden mutation are noted (L), as are symptomatic subjects who had ascertained thrombosis (^*). White squares/circles refer to individuals who were not investigated.