P1’s Noonan-like features (short stature and facial characteristics) and the absence of autoinflammation, HLH and thrombocytopenia in both patients accorded with the location of this variant which, like other N-terminal CDC42 variants, was predicted to interfere with binding to downstream substrates, including PAK1 and WASp [10]. The gene discussed is WAS; the disease is hemophagocytic syndrome.