Severe combined immunodeficiency-19 (IMD19) is an autosomal recessive disorder characterized by onset in early infancy of recurrent bacterial, viral, and fungal infections. Patients usually have chronic diarrhea, recurrent respiratory infections, and failure to thrive. Immunologic workup shows a T cell-negative, B cell-positive, natural killer (NK) cell-positive phenotype. The disorder is lethal in early childhood without bone marrow transplantation (summary by Yu et al., 2011).

IMD24 is an autosomal recessive immunodeficiency characterized by the impaired capacity of activated T and B cells to proliferate in response to antigen receptor-mediated activation. Patients have early onset of severe chronic viral infections, mostly caused by herpesviruses, including Epstein-Barr virus (EBV) and varicella zoster virus (VZV); they also suffer from recurrent encapsulated bacterial infections, a spectrum typical of a combined deficiency of adaptive immunity (CID) (summary by Martin et al., 2014).

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-44 (IMD44) is an autosomal recessive primary immunodeficiency characterized by increased susceptibility to viral infections and adverse multisystemic reaction to vaccination in some patients. Affected individuals appear to have defects in mitochondrial fission and fusion (summary by Shahni et al., 2015).

Hyper-IgE syndrome-2 with recurrent infections (HIES2) is an autosomal recessive immunologic disorder characterized by recurrent staphylococcal infections of the skin and respiratory tract, eczema, elevated serum immunoglobulin E, and hypereosinophilia. It is distinguished from autosomal dominant HIES1 (147060) by the lack of connective tissue and skeletal involvement (Renner et al., 2004). For a discussion of genetic heterogeneity of hyper-IgE syndrome, see 147060. See also TYK2 deficiency (611521), a clinically distinct disease entity that includes characteristic features of both autosomal recessive HIES2 and mendelian susceptibility to mycobacterial disease (MSMD; 209950) (Minegishi et al., 2006).

Immunodeficiency-74 (IMD74) is an X-linked recessive specific immunologic disorder characterized by the development of severe respiratory insufficiency in response to infection with the COVID-19 coronavirus, also known as SARS-CoV-2 ssRNA coronavirus. Affected individuals usually require mechanical ventilation in the ICU in order to survive. Laboratory studies show activation of the immune response and may show perturbation of some values, such as increased D-dimers and fibrinogen. In vitro functional studies of patient immune cells show impaired signaling through the TLR7 pathway, resulting in defective type I and type II interferon (IFN) responses. The patients reported to date did not have a history of immunodeficiency or chronic disease (summary by van Der Made et al., 2020).

Immunodeficiency-91 and hyperinflammation (IMD91) is an autosomal recessive complex immunologic disorder characterized by both immunodeficiency and recurrent infections, often to viruses or mycobacteria, as well as by hyperinflammation with systemic involvement. Affected individuals present in infancy with variable features, including fever, infection, thrombocytopenia, renal or hepatic dysfunction, recurrent infections, or seizures. Most patients eventually develop hepatic or renal failure, compromised neurologic function, lymphadenopathy or hepatosplenomegaly, and multiorgan failure resulting in death. More variable features may include intermittent monocytosis, features of hemophagocytic lymphohistiocytosis (HLH), and serologic evidence of hyperinflammation. The disorder is thought to result from dysregulation of the interferon response to viral stimulation in the innate immune system (summary by Le Voyer et al., 2021; Vavassori et al., 2021).