Immunodeficiency-72 with autoinflammation and lymphoproliferation (IMD72) is an autosomal recessive immunologic disorder characterized by onset of recurrent infections or systemic inflammation in the first year of life. Affected individuals develop bacterial and viral infections that can be severe, including bacteremia, recurrent pneumonia, and meningitis, consistent with an immunodeficiency. There is also an autoimmune and hyperinflammatory aspect to the disorder, manifest as atopy or allergies, hepatosplenomegaly, and lymphoproliferation, including hemophagocytic lymphohistiocytosis (HLH). Immunologic workup shows variable abnormalities, including low or high Ig subsets, increased B cells, irregular T-cell activation and cytokine response, impaired immune synapse formation, and defective cellular migration. At the cellular level, these defects are related to abnormal F-actin polymerization and altered intracellular signaling (summary by Cook et al., 2020).