All arc true about Wiskott-Aldrich syndrome exccpt-
Wiskott-Aldrich syndrome (WAS) is a rare X-linked recessive disease characterized by eczema, thrombocytopenia (low platelet count), immune deficiency, and bloody diarrhea (secondary to the thrombocytopenia). The microthrombocytes seen in WAS patients have only been observed in one other condition, ARPC1B deficiency. In both conditions the defective platelets are thought to be removed from circulation by the spleen and/or liver, leading to low platelet counts. WAS patients have increased susceptibility to infections, paicularly of the ears and sinuses, and this immune deficiency has been linked to decreased antibody production and the inability of immune T cells to effectively combat infection. Genetics WAS is associated with mutations in a gene on the sho arm of the X chromosome (Xp11.23) that was originally termed the Wiskott-Aldrich syndrome protein gene and is officially known as WAS (Gene ID: 7454).X-linked thrombocytopenia is also linked to WAS mutations, although they differ from those that cause full-blown WAS. The rare disorder X-linked neutropenia has also been linked to a specific subset of WAS mutations. The protein product of WAS is known as WASp. It contains 502 amino acids and is mainly expressed in hematopoietic cells (the cells in the bone marrow that develop into blood cells). The main function of WASp is to activate actin polymerization by serving as a nucleation-promoting factor (NPF) for the Arp2/3 complex, which generates branched actin filaments. Several proteins can serve as NPFs, and it has been observed that in WAS platelets the Arp2/3 complex functions normally, indicating that WASp is not required for its activation in platelets. In T-cells, WASp is impoant because it is known to be activated T-cell receptor signaling pathways to induce coical actin cytoskeleton rearrangements that are responsible for forming the immunological synapse. The severity of the symptoms produced by WAS mutations correlate with their effects on WASp. Alleles that produce no or truncated protein have more severe effects than missense mutations. Although autoimmune disease and malignancy may occur with both types of mutations, patients with truncated WASp carry a higher risk. A defect in the CD43 molecule has also been found in WAS patients. Ref Davidson 23rd edition pg 936
Bloody diarrhea during infancy
Low IgM and elevated IgA and IgE
Large size platelets
Atopic dermatitis
Haematology