MedGen

The phenotypic spectrum of X-linked severe combined immunodeficiency (X-SCID) ranges from typical X-SCID (early-onset disease in males that is fatal if not treated with hematopoietic stem cell transplantation [HSCT] or gene therapy) to atypical X-SCID (later-onset disease comprising phenotypes caused by variable immunodeficiency, immune dysregulation, and/or autoimmunity). Typical X-SCID. Prior to universal newborn screening (NBS) for SCID most males with typical X-SCID came to medical attention between ages three and six months because of recurrent infections, persistent infections, and infections with opportunistic organisms. With universal NBS for SCID, the common presentation for typical X-SCID is now an asymptomatic, healthy-appearing male infant. Atypical X-SCID, which usually is not detected by NBS, can manifest in the first years of life or later with one of the following: recurrent upper and lower respiratory tract infections with bronchiectasis; Omenn syndrome, a clinical phenotype caused by immune dysregulation; X-SCID combined immunodeficiency (often with recurrent infections, warts, and dermatitis); immune dysregulation and autoimmunity; or Epstein-Barr virus-related lymphoproliferative complications. [from GeneReviews]

MHC class II deficiency (MHC2D), also known as bare lymphocyte syndrome type II (BLS type II), is a rare autosomal recessive primary immunodeficiency showing genetic heterogeneity. The disorder is characterized by the loss of expression of MHC class II antigens (HLA-DR, HLA-DQ, and HLA-DP) on antigen-presenting cells (APCs) resulting from mutations in regulatory genes required for proper transcription of the MHC class II genes. Affected individuals present in early infancy with severe recurrent infections (bacteria, viruses, fungi, and protozoa), usually affecting the gastrointestinal and respiratory tracts. Protracted diarrhea and failure to thrive is often present. About 20% of patients develop autoimmune features, mainly cytopenias. Laboratory studies show reduced CD4+ T cell counts with an inverted CD4:CD8 ratio, hypogammaglobulinemia, and abnormal lymphocyte proliferation to foreign antigens. Death in infancy or early childhood often occurs, although some patients may have longer survival. MHC type II deficiency may not detected by newborn screening for T-cell receptor excision circles (TRECs). Bone marrow transplantation may be curative, although complications are common (summary by Hanna and Etzioni, 2014; El Hawary et al., 2019). In HLA class II deficiency, the abnormal expression of HLA molecules has been shown to be secondary to defective synthesis (Lisowska-Grospierre et al., 1985), due in turn to an abnormal transacting regulatory gene located outside the major histocompatibility complex (MHC) (Marcadet et al., 1985; de Preval et al., 1985). The transacting regulatory factor, known as RFX, binds to class II promoters and is defective in hereditary HLA deficiency type II, otherwise known as the 'bare lymphocyte syndrome.' The failure of HLA expression leads to immunodeficiency affecting both cellular and humoral responses to antigens. DeSandro et al. (1999) reviewed the molecular bases of the several forms of MHC deficiency. Genetic Heterogeneity of MHC Class II Deficiency MHC2D2 (620815) is caused by mutation in the RFXANK gene (603200); MHC2D3 (620816) and MHC2D5 (620818) are caused by mutation in the RFX5 gene (601863); and MHC2D4 (620817) is caused by mutation in the RFXAP gene (601861). See also MHC class I deficiency (MHC1D1; 604571). [from OMIM]

X-linked lymphoproliferative disease (XLP) has two recognizable subtypes, XLP1 and XLP2. XLP1 is characterized predominantly by one of three commonly recognized phenotypes: Inappropriate immune response to Epstein-Barr virus (EBV) infection leading to hemophagocytic lymphohistiocytosis (HLH) or severe mononucleosis. Dysgammaglobulinemia. Lymphoproliferative disease (malignant lymphoma). XLP2 is most often characterized by HLH (often associated with EBV), dysgammaglobulinemia, and inflammatory bowel disease. HLH resulting from EBV infection is associated with an unregulated and exaggerated immune response with widespread proliferation of cytotoxic T cells, EBV-infected B cells, and macrophages. Dysgammaglobulinemia is typically hypogammaglobulinemia of one or more immunoglobulin subclasses. The malignant lymphomas are typically B-cell lymphomas, non-Hodgkin type, often extranodal, and in particular involving the intestine. [from GeneReviews]

X-linked hyper IgM syndrome (HIGM1), a disorder of abnormal T- and B-cell function, is characterized by low serum concentrations of IgG, IgA, and IgE with normal or elevated serum concentrations of IgM. Mitogen proliferation may be normal, but NK- and T-cell cytotoxicity can be impaired. Antigen-specific responses are usually decreased or absent. Total numbers of B cells are normal but there is a marked reduction of class-switched memory B cells. Defective oxidative burst of both neutrophils and macrophages has been reported. The range of clinical findings varies, even within the same family. More than 50% of males with HIGM1 develop symptoms by age one year, and more than 90% are symptomatic by age four years. HIGM1 usually presents in infancy with recurrent upper- and lower-respiratory tract bacterial infections, opportunistic infections including Pneumocystis jirovecii pneumonia, and recurrent or protracted diarrhea that can be infectious or noninfectious and is associated with failure to thrive. Neutropenia is common; thrombocytopenia and anemia are less commonly seen. Autoimmune and/or inflammatory disorders (such as sclerosing cholangitis) as well as increased risk for neoplasms have been reported as medical complications of this disorder. Significant neurologic complications, often the result of a CNS infection, are seen in 5%-15% of affected males. Liver disease, a serious complication of HIGM1 once observed in more than 80% of affected males by age 20 years, may be decreasing with adequate screening and treatment of Cryptosporidium infection. [from GeneReviews]

X-linked lymphoproliferative disease (XLP) has two recognizable subtypes, XLP1 and XLP2. XLP1 is characterized predominantly by one of three commonly recognized phenotypes: Inappropriate immune response to Epstein-Barr virus (EBV) infection leading to hemophagocytic lymphohistiocytosis (HLH) or severe mononucleosis. Dysgammaglobulinemia. Lymphoproliferative disease (malignant lymphoma). XLP2 is most often characterized by HLH (often associated with EBV), dysgammaglobulinemia, and inflammatory bowel disease. HLH resulting from EBV infection is associated with an unregulated and exaggerated immune response with widespread proliferation of cytotoxic T cells, EBV-infected B cells, and macrophages. Dysgammaglobulinemia is typically hypogammaglobulinemia of one or more immunoglobulin subclasses. The malignant lymphomas are typically B-cell lymphomas, non-Hodgkin type, often extranodal, and in particular involving the intestine. [from GeneReviews]

X-linked lymphoproliferative disease (XLP) has two recognizable subtypes, XLP1 and XLP2. XLP1 is characterized predominantly by one of three commonly recognized phenotypes: Inappropriate immune response to Epstein-Barr virus (EBV) infection leading to hemophagocytic lymphohistiocytosis (HLH) or severe mononucleosis. Dysgammaglobulinemia. Lymphoproliferative disease (malignant lymphoma). XLP2 is most often characterized by HLH (often associated with EBV), dysgammaglobulinemia, and inflammatory bowel disease. HLH resulting from EBV infection is associated with an unregulated and exaggerated immune response with widespread proliferation of cytotoxic T cells, EBV-infected B cells, and macrophages. Dysgammaglobulinemia is typically hypogammaglobulinemia of one or more immunoglobulin subclasses. The malignant lymphomas are typically B-cell lymphomas, non-Hodgkin type, often extranodal, and in particular involving the intestine. [from GeneReviews]

Anhidrotic ectodermal dysplasia with immune deficiency (EDA-ID) is a form of ectodermal dysplasia, which is a group of conditions characterized by abnormal development of ectodermal tissues including the skin, hair, teeth, and sweat glands. In addition, immune system function is reduced in people with EDA-ID. The signs and symptoms of EDA-ID are evident soon after birth, and due to the severity of the immune system problems, most people with this condition survive only into childhood.

Skin abnormalities in children with EDA-ID include areas that are dry, wrinkled, or darker in color than the surrounding skin. Affected individuals tend to have sparse scalp and body hair (hypotrichosis). EDA-ID is also characterized by missing teeth (hypodontia) or teeth that are small and pointed. Most children with EDA-ID have a reduced ability to sweat (hypohidrosis) because they have fewer sweat glands than normal or their sweat glands do not function properly. An inability to sweat (anhidrosis) can lead to a dangerously high body temperature (hyperthermia), particularly in hot weather and during exercise, because the body cannot cool itself by evaporating sweat.

The immune deficiency in EDA-ID varies among individuals with this condition. Children with EDA-ID often produce abnormally low levels of proteins called antibodies or immunoglobulins. Antibodies help protect the body against infection by attaching to specific foreign particles and germs, marking them for destruction. A reduction in antibodies makes it difficult for children with this disorder to fight off infections. In EDA-ID, immune system cells called T cells and B cells have a decreased ability to recognize and respond to foreign invaders (such as bacteria, viruses, and yeast) that have sugar molecules attached to their surface (glycan antigens). Other key aspects of the immune system may also be impaired, leading to recurrent infections.

Children with EDA-ID commonly get infections in the lungs (pneumonia), ears (otitis media), sinuses (sinusitis), lymph nodes (lymphadenitis), skin, bones, and gastrointestinal tract. Approximately one quarter of individuals with EDA-ID have disorders involving abnormal inflammation, such as inflammatory bowel disease or rheumatoid arthritis.

There are two forms of EDA-ID that have similar signs and symptoms and are distinguished by the modes of inheritance: X-linked recessive or autosomal dominant. [from MedlinePlus Genetics]

Immunodeficiency-61 (IMD61) is an X-linked recessive primary immunodeficiency characterized by onset of recurrent infections in early childhood due to impaired antibody production. Affected individuals have normal numbers of circulating B and T cells, but B cells have an intrinsic defect in antibody production (summary by Keller et al., 2018). For a general phenotypic description of X-linked agammaglobulinemia, see 300755. [from OMIM]

X-linked immunodeficiency-98 with autoinflammation (IMD98) is characterized by onset of recurrent infections associated with lymphoproliferation and autoinflammation in the first decade of life. Mostly males are affected; carrier females may have mild symptoms. Laboratory studies show evidence of immune dysregulation, including hypogammaglobulinemia with reduced memory B cells, skewed T-cell subsets, increased levels of proinflammatory cytokines, activated T cells and monocytes, and autoimmune cytopenias, including neutropenia (Aluri et al., 2021; Fejtkova et al., 2022). [from OMIM]

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). [from OMIM]

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). [from OMIM]

A rare T-cell non-Hodgkin lymphoma characterized by infiltration of lymph nodes by neoplastic cells of T follicular helper cell origin with a polymorphous inflammatory background including markedly increased follicular dendritic cells and EBV-positive B-cells, as well as prominent proliferation of high endothelial venules. The spleen, liver, skin, and bone marrow are also frequently involved. Patients typically present with generalized lymphadenopathy, hepatosplenomegaly, systemic symptoms, and polyclonal hypergammaglobulinemia. Pruritic skin rash, arthritis, pleural effusion, and ascites may also be observed. The condition is aggressive with generally poor prognosis. [from ORDO]

Describes a rare group of immunodeficiencies due to specific mutations in the inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase gamma (IKBKG) or the cytochrome b-245, beta polypeptide (CYBB) genes. The clinical manifestation is mycobacterial infections occurring in males. Diagnosis is made by laboratory analysis. Low levels of IFN-gamma and IL-12 production by the patients'' mononuclear cells upon phytohaemagglutinin (PHA) are detected in those with an IKBKG mutation. In addition, an impaired IL-12 production by monocytes upon PHA stimulation by activated T cells is shown. Impaired NADPH activity is demonstrated in vitro in macrophages and B-cell lines in those with a CYBB mutation. A mutational analysis is necessary to identify the exact causative genes involved allowing for the implementation of a specific treatment plan. [from SNOMEDCT_US]