Hi @apb. TTP and ITP are both blood disorders in which there can be potential clotting issues. But they are not the same disease as there are differences between them.
I found two good articles which will help to explain the difference between them.

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder that affects your blood’s tendency to clot. In this disease, tiny clots form throughout your body
https://www.healthline.com/health/thrombotic-thrombocytopenic-purpura
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ITP, or immune thrombocytopenia, is a blood clotting disorder due to a low amount of platelets
https://www.healthline.com/health/idiopathic-thrombocytopenic-purpura-itp
I hope this is helpful for you.