Wiskott-Aldrich syndrome
The Wiskott-Aldrich Syndrome (WAS) is a primary immune deficiency disease involving both T- and B-lymphocytes. In addition, another type of blood cell called platelets, which helps control bleeding, is also affected. Wiskott-Aldrich syndrome is a genetic disease that selectively affects male children because the defect that causes it is on the short arm of the X chromosome. Females have two X chromosomes, one of which is usually normal. Males have only one X chromosome. The syndrome affects one in every 250,000 male children.
In its classic form, the WAS has a characteristic pattern of findings that include: an increased tendency to bleed caused by a reduced number of platelets, recurrent bacterial, viral and fungal infections, and eczema of the skin. In addition, long term observations of patients with the WAS have revealed an increased incidence of malignancies, including lymphoma and leukemia, and an increased incidence of autoimmune diseases in some patients.
Wiskott-Aldrich syndrome protein
The WAS is caused by mutations in the gene which produces a protein named in honor of the disorder, the Wiskott-Aldrich Syndrome Protein (WASP). The WASP gene is located on the short arm of the X chromosome. The majority of these mutations are “unique”. This means that almost every family has its own characteristic mutation of the WASP gene. If the mutation is severe and interferes almost completely with the gene’s ability to produce the WAS protein, the patient has the classic, more severe form of WAS. In contrast, if there is some production of mutated WAS protein, a milder form of disorder may result. The structure of this protein is:
Source: Abbas, Abul K., et al. p. 26
Main characteristics of WAS patients
A reduced number of platelets is a characteristic hallmark of all patients with the WAS..................
