Human immunodeficiency virus (HIV) is a rare cause of thrombotic microangiopathies (TMA), that can present either with normal ADAMTS13 activity (referred as HIV-related TMA) or suppressed ADAMTS13 activity (referred as HIV-related acquired thrombotic thrombocytopenic purpura, aTTP). This evidence concerns the gene ADAMTS13 and thrombotic microangiopathy.