Disease onset usually manifests in the first few years of life, and is characterized by a key triad of clinical symptoms consistent with a high incidence of haemophagocytic lymphohistiocytosis (HLH), often triggered by Epstein–Barr (EBV) infections, and characterized by splenomegaly and inflammatory bowel disease (IBD), particularly with features of CD13. The gene discussed is ANPEP; the disease is inflammatory bowel disease.