Among CIDs with associated or syndromic features, autoimmune and autoinflammatory complications were most frequent in actin-related disorders, including Wiskott–Aldrich syndrome (35.0%) and Actin-Related Protein 2/3 Complex Subunit 1B (ARPC1B) deficiency (66.7%), with autoimmune cytopenias and gastrointestinal disease as the predominant complications. This evidence concerns the gene ARPC1B and hyperinsulinemic hypoglycemia, familial, 4.