A 4-month-old boy presented with spontaneous nose bleeds and bloody diarrhea. There is a history of recurrent chest and ear infections for which the child was frequently hospitalized. On examination, it was found that the child was also suffering from atopic dermatitis and had petechiae all over the body. Blood sample of the child was taken and sent for fuher evaluation. Lab findings suggested abnormally low platelet counts along with eosinophilia and the peripheral blood smear is given below. The gene involved in the above condition is present on which chromosome: -
This clinical picture is classical triad of Wiskott-Aldrich syndrome (WAS) characterized by eczema-thrombocytopenia-immunodeficiency It is caused due to mutations in the gene encoding Wiskott-Aldrich syndrome protein (WASP), which is located at Xp11.23 It has an X linked recessive pattern of inheritance. The thymus is morphologically normal, at least early in the course of the disease. But there is progressive loss of T lymphocytes in the peripheral blood and in the T-cell zones (paracoical areas) of the lymph nodes, with variable defects in cellular immunity. IgM levels in the serum are low, but levels of IgG are usually normal. Paradoxically the levels of IgA and IgE are often elevated. Patients are also prone to developing B-cell lymphomas.
Chromosome 21
Chromosome 23
X-chromosome
Chromosome 1
Integrated QBank