Diagnoses of early deceased patients with PIRD (n = 70 under 5 years of age) were mostly due to disorders with a high risk of hemophagocytic lymphohistiocytosis (81.4%); premature deaths in “innate” IEI were frequently due to IRAK4 or MyD88 deficiencies (Table S4). Here, MYD88 is linked to hemophagocytic syndrome.