Patients’ description. (A) Pedigrees of the affected family. Squares denote males; circles denote females; slash denote deceased family member; solid red and black symbols represent family members with a history of bleeding and heterozygous carriers of the THBD variant (c.1611C>A giving TM₅₃₆), respectively. The arrow indicates the proband. Plasma sTM concentrations were measured by enzyme-linked immunosorbent assay (ELISA; normal value <10 ng/mL). rFIIa was measured in the serum derived from the coagulation of plasma (normal value <30%). (B) FIIa generation assays were performed in PPP and PRP plasma from a control participant and 4 family members affected by the TM₅₃₆ mutation. PPP, platelet-poor plasma; PRP, platelet-rich plasma; rFIIa, residual FIIa.