Idiopathic thrombocytopenic purpura (ITP) Idiopathic thrombocytopenic purpura (ITP) is a bleeding disorder in which the immune system destroys platelets, which are necessary for normal blood clotting. People with the disease have too few platelets in the blood. ITP is sometimes called immune thrombocytopenic purpura or simply, immune thrombocytopenia.
sex-linked disorder - any disease or abnormality that is determined by the sex hormones; hemophilia is determined by a gene defect on an X chromosome. bleeder's disease, haemophilia, hemophilia - congenital tendency to uncontrolled bleeding; usually affects males and is transmitted from mother to son.
This means that almost any gene on the X, even if it is recessive in the female, will be expressed in males. These are referred to as X-linked genes. Genes found only on the Y chromosome are referred to as Y-linked genes, and expressed only in males. Genes on either sex chromosome can be called sex-linked genes. There are approximately 1,098 X-linked genes, though most of them are not for female anatomical characteristics. In fact, many are linked to disorders such as hemophilia, Duchenne muscular dystrophy, fragile-X syndrome and several others.