While WAS typically includes combined immunodeficiency, microthrombocytopenia, and eczema, the clinical and laboratory phenotypes of WIP-deficient patients–including lymphocyte subsets, platelets, lymphocyte proliferation in vitro, and IgE—varied widely and did not entirely recapitulate WAS, impeding early diagnosis in the reported patients. Here, WIPF1 is linked to immune system disorder.