| • | X-linked recessive; seen exclusively in young boys |
| • | gene = WASP gene – involved in the reorganization of the actin cytoskeleton in hematopoietic cells in response to external stimuli. |
| • | the hematopoietic cells of affected patients cannot polarize or migrate in response to physiologic stimuli, accounting for the impaired cell-mediated and humoral immunity and the protean clinical features of the syndrome |
clinical:
| • | triad: chronic eczematous dermatitis, recurrent infections, thrombocytopenia |
| • | skin – chronic eczematous dermatitis (resembling atopic eczema), petechiae |
| • | impaired cell-mediated and humoral immunity – recurrent bacterial infections (pyoderma, suppurative otitis media) |
| • | platelets – thrombocytopenia (petechiae, hepatosplenomegaly, bloody diarrhea, intracranial hemorrhage) |
| • | oncology –lymphoma (10%) |
| • | its first clinical features usually include petechiae, a purpuric dermatitis or a bleeding episode |
| • | prognosis = frequently die in first decade |
| • | treatment = bone marrow transplant (for cure) |
| • | ddx: atopic dermatitis, hyper-IgE syndrome, CGD chronic granulomatous disease, SCID severe combined immunodeficiency disease (bloody diarrhea may help to distinguish from SCID) |
labs:
| • | increased IgA, IgD, IgE; decreased IgM |
| • | decreased platelets (there seems to be an intrinsic platelet abnormality) |
summary:
I like to think of Wiskott-Aldrich syndrome as a disease of the bone marrow; after all it is treated by bone marrow transplant. Many bone marrow derived cells are affected including platelets (thrombocytopenia) and lymphocytes (lymphoma in 10%). The result of such a wide reaching defect is that both cell mediated and humoral immunity are affected. .
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