WASp was the first identified member due to that its loss-of-function leads to the severe immunodeficiency disease Wiskott-Aldrich syndrome (WAS), initially described by Alfred Wiskott in 1937 and Robert Aldrich in 1954 (Wiskott A, Familiärer, angeborener Morbus Werlhofii? The gene discussed is WAS; the disease is Wiskott-Aldrich syndrome.