Hereditary Thrombocythaemia 1 (THPO)
Autosomal dominant
Caused by gain-of-function changes in one copy of THPO, usually in the part of the gene that controls how efficiently the hormone is made. Excess thrombopoietin raises the platelet count.
Signs and symptoms
A persistently high platelet count. Many people have no symptoms, while some develop blood clots or, less often, bleeding. Less often the spleen is enlarged.
What a diagnosis changes
Management is guided by a haematologist and depends on the person's clotting risk. Each child of an affected person may inherit the change, so testing of relatives is recommended.
Genes analysed
Also known as
THCYT1; THPO-related thrombocythemia
