While autoimmune complications are common in WAS, including autoimmune hemolytic anemia, vasculitis, and glomerulonephritis, type 1 diabetes has not been previously described.<h4>Case presentation</h4>We report a 37-year-old man with longstanding leukopenia and recurrent infections who was diagnosed with WAS after genetic testing revealed a gain-of-function mutation in the WAS gene. The gene discussed is WAS; the disease is type 1 diabetes mellitus.