Hyper-IgM syndrome type 2 (HIGM2) is a rare immunodeficiency characterized by normal or elevated serum IgM levels with absence of IgG, IgA, and IgE, resulting in a profound susceptibility to bacterial infections. For a discussion of genetic heterogeneity of immunodeficiency with hyper-IgM, see HIGM1 (308230).

Any severe combined immunodeficiency in which the cause of the disease is a mutation in the CD247 gene.

Any common variable immunodeficiency in which the cause of the disease is a mutation in the CD81 gene.

Immunodeficiency-8 with lymphoproliferation (IMD8) is an autosomal recessive primary immunodeficiency characterized by early-childhood onset of recurrent infections and lymphoproliferative disorders, often associated with EBV infection. Laboratory studies show defects in the numbers and function of certain lymphocyte subsets, particularly T cells (Moshous et al., 2013; Stray-Pedersen et al., 2014).

Combined immunodeficiency due to MALT1 deficiency is a rare, genetic form of primary immunodeficiency characterized by growth retardation, early recurrent pulmonary infections leading to bronchiectasis, inflammatory gastrointestinal disease, and other symptoms, such as rash, dermatitis, skin infections.

Immunodeficiency-62 (IMD62) is an autosomal recessive primary immunologic disorder clinically characterized by onset of recurrent upper and lower respiratory infections late in the first decade of life. Patients may also have increased viral susceptibility to varicella zoster virus (VZV) or herpes simplex virus (HSV). Laboratory studies show impaired antibody response to vaccination, low levels of circulating memory B cells, and almost undetectable antibodies. There is also evidence of secondary T-cell dysfunction. The disorder may result from disturbed actin cytoskeleton dynamics causing impaired lymphocyte migration (summary by Bouafia et al., 2019).

Immunodeficiency-109 with EBV-induced lymphoproliferation (IMD109) is an autosomal recessive primary immune disorder characterized by onset of recurrent sinopulmonary infections in childhood. Affected individuals are susceptible to infection with EBV and develop EBV viremia and EBV-associated lymphoproliferative disease or B-cell lymphoma. Immunologic workup shows normal levels of T, B, and NK cells, with defective CD8+ T cell function after stimulation. Some patients may have hypogammaglobulinemia and poor antibody response to stimulation (Alosaimi et al., 2019).

Common variable immunodeficiency-15 (CVID15) is an autosomal dominant immunologic disorder characterized by the onset of severe recurrent infections in infancy or early childhood. Laboratory studies show hypogammaglobulinemia with antibody deficiencies of IgM, IgG, and IgA due to impaired plasma cell homeostasis, although other B cell subset numbers are normal. T and NK cells are also normal. Treatment with IV Ig results in a favorable clinical response to recurrent infections (Schubert et al., 2018). For a general description and a discussion of genetic heterogeneity of common variable immunodeficiency, see CVID1 (607594).

Autoinflammation with episodic fever and immune dysregulation (AIFID) is an autosomal recessive disorder characterized by recurrent fever and autoinflammation affecting various organ systems. The onset of symptoms is in infancy or early childhood. Clinical features are highly variable and may include lymphadenopathy, inflammation of the joints, gastrointestinal inflammation, and parotitis. Laboratory studies show leukocytosis, often with neutrophilia, and inflammatory markers (C-reactive protein, 123260; erythrocyte sedimentation rate (ESR)), but immunoglobulins and other immune cells are essentially normal, and autoantibodies are not present. The features are consistent with immune dysregulation; some patients may have symptoms of mild immunodeficiency, such as chronic otitis media. Treatment with TNF (191160) inhibitors may result in significant clinical improvement (Oda et al., 2024).