Familial hereditary thrombocytopenia and HLA

Megakaryocytes and inherited thrombocytopenias

Inherited thrombocytopenias may be divided into two groups. In the first group, there is no marked thrombocytopathy. Although numerous in the bone marrow, megakaryocytes often are abnormal cytologically. A dysmegakaryocytopoiesis with defective platelet production is suggested but remains to be evidenced. In the second group, thrombocytopenias are accompanied with variable thrombocytopathy. The functional and biochemical platelet abnormalities responsible for these different thrombocytopathies often are well elucidated. The study of the relations with the occurrence of thrombocytopenia constitutes an interesting field of investigation.

Wiskott-Aldrich syndrome: new molecular and biochemical insights

The Wiskott-Aldrich syndrome is an uncommon X-linked recessive disease characterized by eczema, thrombocytopenia, and immunodeficiency. The clinical features begin early in life and include recurrent infections, bleeding, and severe eczema. Unless the condition is treated by bone marrow transplantation, the prognosis of Wiskott-Aldrich syndrome is grave, and premature death caused by sepsis, hemorrhage, or lymphoreticular malignancy is common. Although the biochemical defect responsible for the syndrome is not known, recent investigations with restriction fragment length polymorphisms have mapped the Wiskott-Aldrich syndrome locus to the proximal portion of the short arm of the human X chromosome (Xp11). The isolation of these DNA markers makes feasible both carrier detection and prenatal diagnosis of Wiskott-Aldrich syndrome and provides an important adjunct to the management of Wiskott-Aldrich syndrome for patients and their families. These genetic data, in conjunction with the recent identification of a specific O-glycosylation defect in lymphocytes from patients with Wiskott-Aldrich syndrome, present an opportunity for the eventual isolation of the Wiskott-Aldrich syndrome gene and identification of the underlying cellular defect. We review the clinical and laboratory features of this syndrome and summarize the new molecular and biochemical approaches that can be used in diagnosis, genetic counseling, and treatment.