31% of the patients had medical underlying conditions, including prematurity < 36 weeks (10.5%), renal anatomical or functional disorders (15.2%), immunodeficiency (3 patients with trisomy 21 and hypogammaglobulinemia, 2 patients with nephrotic syndrome and hypogammaglobulinemia, DiGeorge syndrome, IFNGR2 deficiency, renal transplantation and Wiscott Aldrich syndrome) (4.7%), cardiovascular disease (3.7%), gastrointestinal disease 2.6%)), and others (9.4%). Here, IFNGR2 is linked to immune system disorder.