MHC class II deficiency-3 (MHC2D3) is a rare autosomal recessive immunodeficiency characterized by the onset of recurrent and persistent infections from birth. Infectious agents include bacteria, viruses, fungi, and protozoa, usually affecting the respiratory and gastrointestinal tract. Laboratory studies show decreased CD4+ T cells, hypogammaglobulinemia, an inverted CD4:CD8 ratio, and absence of MHC type II antigens (HLA-DR, -DQ, and -DP) on the surface of antigen-presenting cells. Most patients die in infancy or early childhood unless they undergo bone marrow transplantation, which can be curative, although complications are common. Rare patients may survive longer, even without bone marrow transplant. MHC class II deficiency may not be detected by newborn T-cell receptor excision circle (TREC) screening (summary by El Hawary et al., 2019; Mousavi Khorshidi et al., 2023). For a discussion of genetic heterogeneity of MHC class II deficiency, see MHC2D1 (209920).

Severe combined immunodeficiency (SCID) due to DCLRE1C deficiency is a type of SCID (see this term) characterized by severe and recurrent infections, diarrhea, failure to thrive, and cell sensitivity to ionizing radiation.

Immunodeficiency-9 (IMD9) is an autosomal recessive disorder characterized by early onset of recurrent infections due to defective T-cell activation. Affected individuals also have congenital myopathy resulting in muscle weakness as well as features of ectodermal dysplasia, including soft dental enamel (summary by McCarl et al., 2009).

Autosomal dominant IRF8 deficiency, or IMD32A, causes an abnormal peripheral blood myeloid phenotype with a marked loss of CD11C (ITGAX; 151510)-positive/CD1C (188340)-positive dendritic cells, resulting in selective susceptibility to mycobacterial infections (Hambleton et al., 2011).

Immunodeficiency-20 is a rare autosomal recessive primary immunodeficiency characterized by functional deficiency of NK cells. Patient NK cells are defective in spontaneous cell cytotoxicity, but retain antibody-dependent cellular cytotoxicity. Patients typically present early in childhood with severe herpes viral infections, particularly Epstein Barr virus (EBV), and human papillomavirus (HPV) (summary by Grier et al., 2012).

IMD29 results from autosomal recessive IL12B deficiency and is characterized by undetectable IL12B secretion from leukocytes. IL12B-deficient patients generally present with bacillus Calmette-Guerin (BCG) disease after vaccination in childhood, and at least half also have Salmonella infection. Infections with Mycobacterium tuberculosis and environmental mycobacteria have also been reported in IL12B-deficient patients. The phenotype is relatively mild, and patients have a good prognosis (review by Al-Muhsen and Casanova, 2008).

Immunodeficiency-31A (IMD31A) results from autosomal dominant (AD) STAT1 deficiency. STAT1 is crucial for cellular responses to IFNA (147660)/IFNB (147640) (type I interferon) and IFNG (147570) (type III interferon). AD STAT1 deficiency selectively affects the IFNG pathway, but not the IFNA/IFNB pathway, and confers a predisposition to mycobacterial infections. Pathogens reported in IMD31A patients include bacillus Calmette-Guerin (BCG) and Mycobacterium avium complex, as well as Mycobacterium tuberculosis. IMD31A has low penetrance and a mild clinical phenotype with good prognosis for recovery (review by Al-Muhsen and Casanova, 2008). Two patients with heterozygous STAT1 mutations have been reported with increased susceptibility to adult-onset herpes simplex encephalitis (HSE) without a history of other significant infections (Mork et al., 2015).

IMD38 predisposes individuals to severe clinical disease upon infection with weakly virulent mycobacteria, including Mycobacterium bovis Bacille Calmette-Guerin (BCG) vaccines (Bogunovic et al., 2012). Patients do not experience severe disease in response to viral infection. Affected individuals have intracranial calcification (Zhang et al., 2015).

Immunodeficiency-32B is an autosomal recessive primary immunodeficiency characterized by recurrent infections resulting from variable defects in immune cell development or function, including monocytes, dendritic cells, and natural killer (NK) cells. Patients have particular susceptibility to viral disease (summary by Mace et al., 2017).

Immunodeficiency-69 (IMD69) is an autosomal recessive disorder characterized by increased susceptibility to disseminated mycobacterial infection, including after BCG (bacille Calmette-Guerin) vaccination. Affected individuals develop fever, hepatosplenomegaly, leukocytosis, and thrombocytosis during the acute infection. There appears to be normal immunologic function against other pathogens, including viruses and bacteria. Immunologic work-up shows normal parameters, but patient T and NK cells fail to produce gamma-interferon (IFNG) when stimulated in vitro (summary by Kerner et al., 2020). IMD69 is a form of mendelian susceptibility to mycobacterial disease (MSMD) (see, e.g., IMD27A; 209950).

Immunodeficiency-86 (IMD86) is an autosomal recessive immunologic disorder characterized by susceptibility to mycobacterial disease after exposure to BCG vaccine. Affected individuals usually develop localized mycobacterial lymphadenopathy that can be successfully treated without subsequent episodes (summary by Kong et al., 2018).

X-linked multisystem autoinflammatory disease with immune dysregulation (ADMIDX) is an X-linked recessive disorder with onset of symptoms in infancy or early childhood. Affected individuals may present with variable cytopenias, including anemia, thrombocytopenia, neutropenia, lymphopenia, or hypogammaglobulinemia, and systemic or organ-specific autoinflammatory manifestations. These include skin lesions, panniculitis, inflammatory bowel disease, pulmonary disease, or arthritis associated with recurrent fever, leukocytosis, lymphoproliferation, and hepatosplenomegaly in the absence of an infectious agent. Some patients have circulating autoantibodies that underlie the cytopenias or systemic features, whereas others do not have circulating autoantibodies. In addition, some patients have recurrent infections, whereas others do not show signs of an immunodeficiency. Laboratory studies are consistent with immune dysregulation, including altered B-cell subsets and variably elevated proinflammatory cytokines. Detailed functional studies of platelets, red cells, and T lymphocytes suggest that abnormal actin cytoskeleton remodeling is a basic defect, indicating that this disorder can be classified as an immune-related actinopathy. Severe complications of the disease may result in death in childhood (Boussard et al., 2023; Block et al., 2023).

Immunodeficiency-112 (IMD112) is an autosomal recessive primary immunologic disorder with variable manifestations beginning in early childhood. Some patients have recurrent bacterial, viral, and fungal infections, including disseminated bacillus Calmette-Guerin (BCG)-related infections, whereas at least 1 patient only presented with BCG-related infections. Immunologic workup shows variable abnormalities affecting lymphoid immunity, including hypogammaglobulinemia, lymphopenia or paradoxical lymphocytosis, and defects in B, T, and NK cell differentiation and function mainly due to disruption of the noncanonical NFKB (see 164011) signaling pathway (Willmann et al., 2014; Schlechter et al., 2017).

X-linked recessive immunodeficiency-118 (IMD118) is characterized by increased susceptibility to the development of disseminated mycobacterial infections in infancy, notably after BCG vaccination. Affected males usually recover with treatment, have no other infections, and show normal growth and development. Immunologic workup shows normal numbers of circulating leukocyte subsets, but functional studies show impaired JAK2 (147796) translation in certain T lymphocytes, resulting in defective IL23 (see 605580)-dependent induction of IFNG (147570) production and secretion from other immune cells (Bohlen et al., 2023).

Immunodeficiency-117 (IMD117) is an autosomal recessive immunologic disorder characterized by increased susceptibility to disseminated mycobacterial infection apparent in early childhood. Affected individuals develop mycobacterial disease after BCG (bacille Calmette-Guerin) vaccination and show increased susceptibility to other mycobacterial infections, such as M. avium. Immunologic workup shows impaired development of myeloid and lymphoid cell subsets that secrete and respond to gamma-interferon (IFNG; 147570) (et al., 2023).