TTP may be either inherited or acquired.
There’s an inherited form of TTP that transmits as an autosomal recessive trait. This means that both parents of an affected individual must carry a copy of the abnormal gene.
The parents don’t usually have symptoms of TTP.
This genetic form of TTP results from a mutation in the ADAMTS13 gene. This gene plays a role in the production of an enzyme that causes your blood to clot normally.
Enzymes are special proteins that increase the rate of metabolic chemical reactions. Abnormal clotting occurs when the ADAMTS13 enzyme isn’t present.
In other cases, your body mistakenly produces proteins that interfere with the ADAMTS13 enzyme’s job. This is known as acquired TTP.
You can get acquired TTP in a variety of ways. You can develop it if you have HIV, for example. You can also develop it after certain medical procedures, such as a blood and marrow stem cell transplant and surgery.
In some cases, TTP can develop during pregnancy or if you have cancer or an infection.
Some medications can lead to the development of TTP. These include:
- hormone therapy
- estrogen, as used in birth control or hormone therapy
- cyclosporine (Neoral, Sandimmune), an immunosuppressant drug