TY - JOUR T1 - Report of two unrelated cases of Familial Thrombotic Thrombocytopeic Purpura TT - JF - SSU JO - SSU VL - 11 IS - 3 UR - http://ijpho.ssu.ac.ir/article-1-644-en.html Y1 - 2021 SP - 211 EP - 215 KW - ADAMTS13 KW - Hemolytic anemia KW - Thrombotic Thrombocytopenic Purpura N2 - Thrombotic Thrombocytopenic Purpura (TTP) is a rare microangiopathic disorder characterised by the pentad of microangiopathic hemolytic anemia, thrombocytopenic purpura, neurologic abnormalities, fever, and renal disease. Decreased production and/or activity of ADAMTS13 is the cause of this disorder. ADAMTS13 is a metalloproteinase which is responsible of the cleavage of high weight multimers of von Wilebrand factor. Its acquired form is usually seen in adults and is due to antibody formation against the enzyme. But even rarer familial and relapsing forms (Upshow-Scholman syndrome) are due to enzyme underproduction and can be seen in pediatric age group. Here, the authors reported two unrelated cases of familial TTP from Guilan province in the north of Iran. M3 10.18502/ijpho.v11i3.6571 ER -