Bloom syndrome (BSyn) is characterized by severe pre- and postnatal growth deficiency, immune abnormalities, sensitivity to sunlight, insulin resistance, and a high risk for many cancers that occur at an early age. Despite their very small head circumference, most affected individuals have normal intellectual ability. Women may be fertile but often have early menopause, and men tend to be infertile, with only one confirmed case of paternity. Serious medical complications that are more common than in the general population and that also appear at unusually early ages include chronic obstructive pulmonary disease, diabetes mellitus as a result of insulin resistance, and cancer of a wide variety of types and anatomic sites.

The WAS-related disorders, which include Wiskott-Aldrich syndrome, X-linked thrombocytopenia (XLT), and X-linked congenital neutropenia (XLN), are a spectrum of disorders of hematopoietic cells, with predominant defects of platelets and lymphocytes caused by pathogenic variants in WAS. WAS-related disorders usually present in infancy. Affected males have thrombocytopenia with intermittent mucosal bleeding, bloody diarrhea, and intermittent or chronic petechiae and purpura; eczema; and recurrent bacterial and viral infections, particularly of the ear. At least 40% of those who survive the early complications develop one or more autoimmune conditions including hemolytic anemia, immune thrombocytopenic purpura, immune-mediated neutropenia, rheumatoid arthritis, vasculitis, and immune-mediated damage to the kidneys and liver. Individuals with a WAS-related disorder, particularly those who have been exposed to Epstein-Barr virus (EBV), are at increased risk of developing lymphomas, which often occur in unusual, extranodal locations including the brain, lung, or gastrointestinal tract. Males with XLT have thrombocytopenia with small platelets; other complications of Wiskott-Aldrich syndrome, including eczema and immune dysfunction, are usually mild or absent. Males with XLN have congenital neutropenia, myeloid dysplasia, and lymphoid cell abnormalities.

X-linked agammaglobulinemia (XLA) is characterized by recurrent bacterial infections in affected males in the first two years of life. Recurrent otitis is the most common infection prior to diagnosis. Conjunctivitis, sinopulmonary infections, diarrhea, and skin infections are also frequently seen. Approximately 60% of individuals with XLA are recognized as having immunodeficiency when they develop a severe, life-threatening infection such as pneumonia, empyema, meningitis, sepsis, cellulitis, or septic arthritis. S pneumoniae and H influenzae are the most common organisms found prior to diagnosis and may continue to cause sinusitis and otitis after diagnosis and the initiation of gammaglobulin substitution therapy. Severe, difficult-to-treat enteroviral infections (often manifest as dermatomyositis or chronic meningoencephalitis) can be prevented by this treatment. The prognosis for individuals with XLA has improved markedly in the last 25 years as a result of earlier diagnosis, the development of preparations of gammaglobulin that allow normal concentrations of serum IgG to be achieved, and more liberal use of antibiotics.

Sneddon syndrome is a noninflammatory arteriopathy characterized by onset of livedo reticularis in the second decade and onset of cerebrovascular disease in early adulthood (summary by Bras et al., 2014). Livedo reticularis occurs also with polyarteritis nodosa, systemic lupus erythematosus, and central thrombocythemia, any one of which may be accompanied by cerebrovascular accidents (Bruyn et al., 1987).

Transcobalamin II deficiency (TCN2D) is an autosomal recessive disorder with onset in early infancy characterized by failure to thrive, megaloblastic anemia, and pancytopenia. Other features include methylmalonic aciduria, recurrent infections, and vomiting and diarrhea. Treatment with cobalamin results in clinical improvement, but the untreated disorder may result in mental retardation and neurologic abnormalities (summary by Haberle et al., 2009). Hall (1981) gave a clinically oriented review of congenital defects of vitamin B12 transport, and Frater-Schroder (1983) gave a genetically oriented review.

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.

Primary immunodeficiency syndrome due to p14 deficiency is characterised by short stature, hypopigmentation, coarse facies and frequent bronchopulmonary <i>Streptococcus pneumoniae</i> infections.

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.

Caspase 8 deficiency is a syndrome of lymphadenopathy and splenomegaly, marginal elevation of 'double-negative T cells' (DNT; T-cell receptor alpha/beta+, CD4-/CD8-), defective FAS-induced apoptosis, and defective T-, B-, and natural killer (NK)-cell activation, with recurrent bacterial and viral infections (summary by Madkaikar et al., 2011).

Persistent polyclonal B-cell lymphocytosis (PPBL) is characterized by chronic, stable, persistent, and polyclonal lymphocytosis, the presence of binucleated lymphocytes in the peripheral blood, and a polyclonal increase in serum IgM. It is significantly associated with cigarette smoking (summary by Cornet et al., 2009).

Adenosine deaminase (ADA) deficiency is a systemic purine metabolic disorder that primarily affects lymphocyte development, viability, and function. The clinical phenotypic spectrum includes: Severe combined immunodeficiency disease (SCID), often diagnosed by age six months and usually by age 12 months; Less severe "delayed" onset combined immune deficiency (CID), usually diagnosed between age one and ten years; "Late/adult onset" CID, diagnosed in the second to fourth decades; Benign "partial ADA deficiency" (very low or absent ADA activity in erythrocytes but greater ADA activity in nucleated cells), which is compatible with normal immune function. Infants with typical early-onset ADA-deficient SCID have failure to thrive and opportunistic infections associated with marked depletion of T, B, and NK lymphocytes, and an absence of both humoral and cellular immune function. If immune function is not restored, children with ADA-deficient SCID rarely survive beyond age one to two years. Infections in delayed- and late-onset types (commonly, recurrent otitis, sinusitis, and upper respiratory) may initially be less severe than those in individuals with ADA-deficient SCID; however, by the time of diagnosis these individuals often have chronic pulmonary insufficiency and may have autoimmune phenomena (cytopenias, anti-thyroid antibodies), allergies, and elevated serum concentration of IgE. The longer the disorder goes unrecognized, the more immune function deteriorates and the more likely are chronic sequelae of recurrent infection.

Immunodeficiency-33 (IMD33) is an X-linked recessive disorder that affects only males. It is characterized by early-onset severe infections, usually due to pneumococcus, H. influenzae, and atypical mycobacteria, although other organisms have also been detected. Immunologic investigations may show variable abnormalities or may be normal. Disturbances include dysgammaglobulinemia with hypogammaglobulinemia, decreased IgG2, aberrant levels of IgM and IgA, and decreased class-switched memory B cells. There is often poor, but variable, response to vaccination; in particular, most patients do not develop antibodies to certain polysaccharide vaccines, notably pneumococcus. Other immunologic abnormalities may include impaired NK cytotoxic function, impaired cytokine production upon stimulation with IL1B (147720) or TNFA (191160), low IL6 (147620), low IL12 (see 161561), and decreased IFNG (147570). Patients do not have overt abnormalities of T-cell proliferation, although signaling pathways, such as CD40LG (300386)/CD40 (109535), may be disturbed. There is heterogeneity in the immunologic phenotype, resulting in highly variable clinical courses, most likely due to the different effects of hypomorphic mutations. Treatment with antibiotics and IVIg is usually beneficial; hematopoietic stem cell transplantation may not be necessary, but can be effective. Features of hypohidrotic ectodermal dysplasia are generally not present, although some patients may have conical teeth or hypodontia (summary by Orange et al., 2004, Filipe-Santos et al., 2006, Salt et al., 2008, Heller et al., 2020).

A few individuals have been diagnosed with intermediate autosomal osteopetrosis (IAO), a form of the disorder that can have either an autosomal dominant or an autosomal recessive pattern of inheritance. The signs and symptoms of this condition become noticeable in childhood and include an increased risk of bone fracture and anemia. People with this form of the disorder typically do not have life-threatening bone marrow abnormalities. However, some affected individuals have had abnormal calcium deposits (calcifications) in the brain, intellectual disability, and a form of kidney disease called renal tubular acidosis.\n\nOther features of autosomal recessive osteopetrosis can include slow growth and short stature, dental abnormalities, and an enlarged liver and spleen (hepatosplenomegaly). Depending on the genetic changes involved, people with severe osteopetrosis can also have brain abnormalities, intellectual disability, or recurrent seizures (epilepsy).\n\nAutosomal recessive osteopetrosis (ARO) is a more severe form of the disorder that becomes apparent in early infancy. Affected individuals have a high risk of bone fracture resulting from seemingly minor bumps and falls. Their abnormally dense skull bones pinch nerves in the head and face (cranial nerves), often resulting in vision loss, hearing loss, and paralysis of facial muscles. Dense bones can also impair the function of bone marrow, preventing it from producing new blood cells and immune system cells. As a result, people with severe osteopetrosis are at risk of abnormal bleeding, a shortage of red blood cells (anemia), and recurrent infections. In the most severe cases, these bone marrow abnormalities can be life-threatening in infancy or early childhood.\n\nIn individuals with ADO who develop signs and symptoms, the major features of the condition include multiple bone fractures after minor injury, abnormal side-to-side curvature of the spine (scoliosis) or other spinal abnormalities, arthritis in the hips, and a bone infection called osteomyelitis. These problems usually become apparent in late childhood or adolescence.\n\nAutosomal dominant osteopetrosis (ADO), which is also called Albers-Schönberg disease, is typically the mildest type of the disorder. Some affected individuals have no symptoms. In affected people with no symptoms, the unusually dense bones may be discovered by accident when an x-ray is done for another reason. \n\nOsteopetrosis is a bone disease that makes bone tissue abnormally compact and dense and also prone to breakage (fracture). Researchers have described several major types of osteopetrosis, which are usually distinguished by their pattern of inheritance: autosomal dominant or autosomal recessive. The different types of the disorder can also be distinguished by the severity of their signs and symptoms.

Immunodeficiency-10 (IMD10) is an autosomal recessive primary immunodeficiency characterized by onset of recurrent infections in childhood due to defective T- and NK-cell function, although the severity is variable. Affected individuals may also have hypotonia, hypohidrosis, or dental enamel hypoplasia consistent with amelogenesis imperfecta (summary by Parry et al., 2016).

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).

Congenital disorders of glycosylation (CDG), previously called carbohydrate-deficient glycoprotein syndromes (CDGSs), are a group of hereditary multisystem disorders first recognized by Jaeken et al. (1980). The characteristic biochemical abnormality of CDGs is the hypoglycosylation of glycoproteins, which is routinely determined by isoelectric focusing (IEF) of serum transferrin. Type I CDG comprises those disorders in which there is a defect in the assembly of lipid-linked oligosaccharides or their transfer onto nascent glycoproteins, whereas type II CDG comprises defects of trimming, elongation, and processing of protein-bound glycans. CDG1G is a multisystem disorder characterized by impaired psychomotor development, dysmorphic features, failure to thrive, male genital hypoplasia, coagulation abnormalities, and immune deficiency. More variable features include skeletal dysplasia, cardiac anomalies, ocular abnormalities, and sensorineural hearing loss. Some patients die in the early neonatal or infantile period, whereas others are mildly affected and live to adulthood (summary by Tahata et al., 2019). For a general discussion of CDGs, see CDG1A (212065).

Myotonic dystrophy type 2 (DM2) is characterized by myotonia and muscle dysfunction (proximal and axial weakness, myalgia, and stiffness), and less commonly by posterior subcapsular cataracts, cardiac conduction defects, insulin-insensitive type 2 diabetes mellitus, and other endocrine abnormalities. While myotonia (involuntary muscle contraction with delayed relaxation) has been reported during the first decade, onset is typically in the third to fourth decade, most commonly with fluctuating or episodic muscle pain that can be debilitating and proximal and axial weakness of the neck flexors and the hip flexors. Subsequently, weakness occurs in the elbow extensors and finger flexors. Facial weakness and weakness of the ankle dorsiflexors are less common. Myotonia rarely causes severe symptoms. In a subset of individuals, calf hypertrophy in combination with brisk reflexes is notable.

Common variable immunodeficiency (CVID) is a clinically and genetically heterogeneous group of disorders characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections, and an inability to mount an antibody response to antigen. The defect results from a failure of B-cell differentiation and impaired secretion of immunoglobulins; the numbers of circulating B cells are usually in the normal range, but can be low. Most individuals with CVID have onset of infections after age 10 years. CVID represents the most common form of primary immunodeficiency disorders and is the most common form of primary antibody deficiency. Approximately 10 to 20% of patients with a diagnosis of CVID have a family history of the disorder (reviews by Chapel et al., 2008, Conley et al., 2009, and Yong et al., 2009). Genetic Heterogeneity of Common Variable Immunodeficiency Common variable immunodeficiency is a genetically heterogeneous disorder. See also CVID2 (240500), caused by mutation in the TACI gene (TNFRSF13B; 604907); CVID3 (613493), caused by mutation in the CD19 gene (107265); CVID4 (613494), caused by mutation in the BAFFR gene (TNFRSF13C; 606269); CVID5 (613495), caused by mutation in the CD20 gene (112210); CVID6 (613496), caused by mutation in the CD81 gene (186845); CVID7 (614699), caused by mutation in the CD21 gene (CR2; 120650); CVID8 (614700), caused by mutation in the LRBA gene (606453); CVID10 (615577), caused by mutation in the NFKB2 gene (164012); CVID11 (615767), caused by mutation in the IL21 gene (605384); CVID12 (616576), caused by mutation in the NFKB1 gene (164011); CVID13 (616873), caused by mutation in the IKZF1 gene (603023); CVID14 (617765), caused by mutation in the IRF2BP2 gene (615332); and CVID15 (620670), caused by heterozygous mutation in the SEC61A1 gene (609213). The disorder formerly designated CVID9 has been found to be a form of autoimmune lymphoproliferative disorder; see ALPS3 (615559).

Lung fibrosis-immunodeficiency-46,XX gonadal dysgenesis syndrome is characterised by immune deficiency, gonadal dysgenesis and fatal lung fibrosis. So far, it has been described in two sisters born to consanguineous parents. Both karyotypes were normal female (46,XX). No genetic anomalies could be identified by comparative genome hybridization analysis of their genomes or by analysis of genes known to be associated with these types of anomalies.

Any autosomal agammaglobulinemia in which the cause of the disease is a mutation in the CD79B gene.

Any autosomal agammaglobulinemia in which the cause of the disease is a mutation in the IGLL1 gene.

Any autosomal agammaglobulinemia in which the cause of the disease is a mutation in the BLNK gene.

A syndromic X-linked intellectual disability characterized by moderate intellectual disability, seizures, dysmorphic facial features and in some older patients slowly progressive unsteady gait and progressive weakness that has material basis in variation in the chromosomal region Xq21.33-q23.

Immunodeficiency, centromeric instability, and facial dysmorphism (ICF) syndrome is a rare autosomal recessive disorder characterized by facial dysmorphism, immunoglobulin deficiency resulting in recurrent infections, and mental retardation. Laboratory studies of patient cells show hypomethylation of satellite regions of chromosomes 1, 9, and 16, as well as pericentromeric chromosomal instability in response to phytohemagglutinin stimulation (summary by de Greef et al., 2011). For a discussion of genetic heterogeneity of immunodeficiency-centromeric instability-facial anomalies syndrome, see ICF1 (242860).

Common variable immunodeficiency-8 with autoimmunity is an autosomal recessive disorder of immune dysregulation. Affected individuals have early childhood onset of recurrent infections, particularly respiratory infections, and also develop variable autoimmune disorders, including idiopathic thrombocytopenic purpura, autoimmune hemolytic anemia, and inflammatory bowel disease. The presentation and phenotype are highly variable, even within families (summary by Lopez-Herrera et al., 2012 and Alangari et al., 2012). Immunologic findings are also variable and may include decreased B cells, hypogammaglobulinemia, and deficiency of CD4+ T regulatory (Treg) cells (Charbonnier et al., 2015). For a general description and a discussion of genetic heterogeneity of common variable immunodeficiency, see CVID1 (607594).

Autoinflammation, antibody deficiency, and immune dysregulation (APLAID) is an autosomal dominant systemic disorder characterized by recurrent blistering skin lesions with a dense inflammatory infiltrate and variable involvement of other tissues, including joints, the eye, and the gastrointestinal tract. Affected individuals have a mild humoral immune deficiency associated with recurrent sinopulmonary infections, but no evidence of circulating autoantibodies (summary by Zhou et al., 2012).

FILS syndrome is characterized by mild facial dysmorphism, mainly malar hypoplasia, livedo on the skin since birth, immunodeficiency resulting in recurrent infections, and short stature (summary by Pachlopnik Schmid et al., 2012).

Common variable immunodeficiency-10 (CVID10) is an autosomal dominant primary immunodeficiency characterized by childhood-onset of recurrent infections, hypogammaglobulinemia, and decreased numbers of memory and marginal zone B cells. Some patients may develop autoimmune features and have circulating autoantibodies. An unusual feature is central adrenal insufficiency (summary by Chen et al., 2013). For a general description and a discussion of genetic heterogeneity of common variable immunodeficiency, see CVID1 (607594).

Immunodeficiency-18 is an autosomal recessive primary immunodeficiency characterized by onset in infancy or early childhood of recurrent infections. The severity is variable, encompassing both a mild immunodeficiency and severe combined immunodeficiency (SCID), resulting in early death without bone marrow transplantation in some patients. Immunologic work-up of the IMD18 SCID patients shows a T cell-negative, B cell-positive, natural killer (NK) cell-positive phenotype, whereas T-cell development is not impaired in the mild form of IMD18 (summary by de Saint Basile et al., 2004).

Immunodeficiency-22 (IMD22) is an autosomal recessive disorder characterized by the onset of recurrent bacterial, viral, and fungal respiratory, gastrointestinal, and skin infections in infancy or early childhood. Immunologic workup shows severe T-cell lymphopenia, particularly affecting the CD4+ subset, and impaired proximal TCR intracellular signaling and activation. Although NK cells and B cells are normal, some patients may have hypogammaglobulinemia secondary to the T-cell defect. There are variable manifestations, likely due to the severity of the particular LCK mutation: patients may develop prominent skin lesions resembling epidermodysplasia verruciformis, gastrointestinal inflammation, and virus-induced malignancy. The disease can be fatal in childhood, but hematopoietic stem cell transplant (HSCT) may be curative (Hauck et al., 2012; Li et al., 2016; Keller et al., 2023).

Immune dysregulation with autoimmunity, immunodeficiency, and lymphoproliferation (IDAIL) is an autosomal dominant complex immune disorder with highly variable presentation and clinical manifestations. Prominent features include recurrent infections often associated with hypogammaglobulinemia, autoimmune features such as autoimmune cytopenias, and abnormal lymphocytic infiltration of nonlymphoid organs, including the lungs, brain, and gastrointestinal tract, resulting in enteropathy. Laboratory studies often show lymphopenia and abnormal T and B cell subsets. The variable features are a result of impaired function of Treg cells, which play a role in immune homeostasis (summary by Kuehn et al., 2014; Schwab et al., 2018, and Lopez-Nevado et al., 2021). The disorder shows overlapping features with autoimmune lymphoproliferative syndrome (ALPS); for a general description and a discussion of genetic heterogeneity of ALPS, see 601859.

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).

Immunodeficiency-47 (IMD47) is an X-linked recessive complex syndrome characterized by liver dysfunction, recurrent bacterial infections, hypogammaglobulinemia, and defective glycosylation of serum proteins. Some patients also have neurologic abnormalities (summary by Jansen et al., 2016).

IMD11B is an autosomal dominant disorder of immune dysfunction characterized by onset of moderate to severe atopic dermatitis in early childhood. Some patients may have recurrent infections and other variable immune abnormalities. Laboratory studies show defects in T-cell activation, increased IgE, and eosinophilia (summary by Ma et al., 2017).

B-cell expansion with NFKB and T-cell anergy is an autosomal dominant disorder characterized by onset in infancy of splenomegaly and polyclonal expansion of B cells, resulting in peripheral lymphocytosis. Affected individuals also show mild immune dysfunction, including some defective antibody responses and T-cell anergy. There may be a predisposition to the development of B-cell malignancy (summary by Snow et al., 2012).

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).

Krakow-type spondyloepimetaphyseal dysplasia is characterized by severe skeletal dysplasia, severe immunodeficiency, and developmental delay (Csukasi et al., 2018).

Immunodeficiency-60 and autoimmunity (IMD60) is an autosomal dominant primary immunologic disorder characterized by inflammatory bowel disease and recurrent sinopulmonary infections. The age at symptom onset is highly variable, ranging from infancy to mid-adulthood. Laboratory studies show dysregulation of both B and T cells, with variably decreased immunoglobulin production, decreased T-regulatory cells, and overall impaired lymphocyte maturation (summary by Afzali et al., 2017).

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).

Hyper-IgE syndrome-5 with recurrent infections (HEIS5) is an autosomal recessive immunologic disorder characterized by onset of recurrent sinopulmonary and deep skin infections in early childhood. The infections are mostly caused by bacteria, including H. influenza and Staphylococcus aureus. Additional features include atopic dermatitis, impaired inflammatory responses during infection, increased serum IgE, and increased IL6 (147620) (summary by Spencer et al., 2019). For a discussion of genetic heterogeneity of hyper-IgE syndrome, see HIES1 (147060).

Immunodeficiency-70 (IMD70) is an autosomal dominant immunologic disorder characterized by severe cutaneous warts on the hands, feet, and face, suggesting increased susceptibility to human papillomavirus (HPV) infection. Affected individuals may also have recurrent bacterial infections, such as sinusitis, as well as feature of autoinflammation, such as colitis, celiac disease, and retinal vasculitis. Laboratory studies show decreased CD4+ T cells and decreased CD19+ B cells; hypogammaglobulinemia has also been observed (summary by Thaventhiran et al., 2020).

Autosomal recessive primary immunodeficiency-14B (IMD14B) is characterized by onset of recurrent infections in early childhood. Most patients have respiratory infections, but some may develop inflammatory bowel disease or osteomyelitis. Laboratory studies tend to show hypogammaglobulinemia and decreased levels of B cells. Although NK cell and T cell numbers are normal, there may be evidence of impaired immune-mediated cytotoxicity and defective T-cell function (summary by et al., 2018 and et al., 2019).

Immunodeficiency-82 with systemic inflammation (IMD82) is a complex autosomal dominant immunologic disorder characterized by recurrent infections with various organisms, as well as noninfectious inflammation manifest as lymphocytic organ infiltration with gastritis, colitis, and lung, liver, CNS, or skin disease. One of the more common features is inflammation of the stomach and bowel. Most patients develop symptoms in infancy or early childhood; the severity is variable. There may be accompanying fever, elevated white blood cell count, decreased B cells, hypogammaglobulinemia, increased C-reactive protein (CRP; 123260), and a generalized hyperinflammatory state. Immunologic workup shows variable B- and T-cell abnormalities such as skewed subgroups. Patients have a propensity for the development of lymphoma, usually in adulthood. At the molecular level, the disorder results from a gain-of-function mutation that leads to constitutive and enhanced activation of the intracellular inflammatory signaling pathway. Treatment with SYK inhibitors rescued human cell abnormalities and resulted in clinical improvement in mice (Wang et al., 2021).

Immunodeficiency-85 and autoimmunity (IMD85) is an autosomal dominant immunologic disorder characterized by onset of atopic eczema and recurrent respiratory infections in the first decade of life. Affected individuals also develop autoimmune enteropathy with vomiting, diarrhea, and poor overall growth. More variable features may include autoimmune oligoarthritis, interstitial pneumonitis, and EBV viremia. Laboratory studies show hypogammaglobulinemia and abnormal T-cell function, consistent with a combined immunodeficiency (Keskitalo et al., 2019).

X-linked systemic autoinflammatory disease (SAIDX) is characterized by the onset of systemic autoinflammation in the first months of life. Features include lymphadenopathy, hepatosplenomegaly, fever, panniculitis, and nodular skin rash. Additional manifestations may include inflammation of the optic nerve, intracranial hemorrhage, and lipodystrophy. Laboratory studies show hypogammaglobulinemia, increased or decreased white blood cell count, autoimmune cytopenias, elevated serum inflammatory markers, and a type I interferon signature (de Jesus et al., 2020 and Lee et al., 2022).

Immunodeficiency-102 (IMD102) is an X-linked recessive immunologic disorder characterized by the onset of recurrent sinopulmonary, mucosal, and other infections in early childhood, usually accompanied by refractory autoimmune cytopenias. Affected individuals have bacterial, viral, and fungal infections, as well as hemolytic anemia, thrombocytopenia, lymphopenia, and decreased NK cells. Laboratory studies show defective T-cell proliferation and function, likely due to signaling abnormalities. The disorder may also manifest as a hyperinflammatory state with immune dysregulation (Delmonte et al., 2021).

Immunodeficiency-93 and hypertrophic cardiomyopathy (IMD93) is an autosomal recessive disorder characterized by onset of recurrent viral and bacterial infections, particularly with encapsulated bacteria, and hypertrophic cardiomyopathy in the first months or years of life. Immunologic workup typically shows decreased circulating B cells and hypo- or agammaglobulinemia, sometimes with neutropenia or T-cell lymphocytosis, although laboratory findings may be variable among patients. Ig replacement therapy is beneficial. Cardiac involvement can also include atrial septal defect, valvular insufficiency, and pre-excitation syndrome. Rare myopathic or neurologic involvement has been reported, but these features are not consistently part of the disorder and may be related to other genetic defects (summary by Niehues et al., 2020 and Saettini et al., 2021).

Autosomal dominant agammaglobulinemia-10 (AGM10) is characterized by early-childhood onset of recurrent viral and bacterial infections affecting various organ systems, particularly the sinopulmonary system. Laboratory studies show low or absent circulating B cells and hypo- or agammaglobulinemia. Affected individuals may have adverse reactions to certain vaccinations, such as the polio vaccine. Treatment with replacement Ig is effective; hematopoietic stem cell transplantation has also been reported (summary by Le Coz et al., 2021). For a discussion of genetic heterogeneity of autosomal agammaglobulinemia, see AGM1 (601495).

Hyper-IgE syndrome-4A with recurrent infections (HIES4A) is an autosomal dominant immunologic disorder characterized by recurrent, mainly sinopulmonary infections associated with increased serum IgE. The phenotype is variable, even within families. Some patients have onset of symptoms in early childhood and develop complications, including bronchiectasis or hemoptysis, whereas others have later onset of less severe infections. Immunologic workup usually shows normal leukocyte levels, although some patients may demonstrate alterations in lymphocyte subsets, including T cells. Affected individuals also have variable skeletal abnormalities, including high-arched palate, hyperextensible joints, scoliosis, and bone fractures. The IL6ST mutations are loss-of-function, although the truncated mutant proteins are expressed and interfere with the wildtype protein in a dominant-negative manner by disrupting IL6 (147620) and IL11 (147681) signaling (summary by Beziat et al., 2020). For a discussion of genetic heterogeneity of hyper-IgE syndrome, see HIES1 (147060).

Immunodeficiency-96 (IMD96) is an autosomal recessive disorder characterized by onset of recurrent, usually viral, respiratory infections in infancy or early childhood. Other infections, including gastrointestinal and urinary tract infections, may also occur. Laboratory studies show hypogammaglobulinemia, lymphopenia with increased gamma/delta T cells, and erythrocyte macrocytosis. The disorder results from defective cellular DNA repair (summary by Maffucci et al., 2018).

Immunodeficiency-97 with autoinflammation (IMD97) is an autosomal recessive complex immunologic disorder with variable features. Affected individuals present in the first decade of life with inflammatory interstitial lung disease or colitis due to abnormal tissue infiltration by activated T cells. Patients develop autoimmune cytopenias and may have lymphadenopathy; 1 reported patient had features of hemophagocytic lymphohistiocytosis (HLH; see FHL1, 267700). Some patients may have recurrent infections associated with mild lymphopenia, hypogammaglobulinemia, and NK cell dysfunction. Immunologic workup indicates signs of significant immune dysregulation with elevation of inflammatory serum markers, variable immune cell defects involving neutrophils, NK cells, and myeloid cells, and disrupted levels of T regulatory cells (Tregs). Two unrelated patients have been reported (summary by Takeda et al., 2019 and Thian et al., 2020).

Autosomal recessive agammaglobulinemia-8B (AGM8B) is characterized by onset of recurrent infections in early childhood. Laboratory studies of affected individuals show decreased circulating immunoglobulins and decreased peripheral B cells. More variable features may include dysmorphic facies and subtle abnormalities of other immune cells, such as T cells. One patient who developed childhood B-cell acute lymphocytic leukemia (B-ALL) has been described (summary by Ben-Ali et al., 2017).

Immunodeficiency-105 (IMD105) is an autosomal recessive disorder characterized by onset of recurrent infections in early infancy. Manifestations may include pneumonia, dermatitis, and lymphadenopathy. B-cell lymphoma was reported in 1 patient. Laboratory studies show decreased or absent numbers of nonfunctional T cells, normal or increased levels of B cells, hypogammaglobulinemia, and normal or low NK cells. The disorder is caused by a deficiency of transmembrane protein CD45 (PTPRC) on leukocytes, which plays an important role in T- and B-cell development (Cale et al., 1997; Kung et al., 2000). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal recessive SCID, see 601457.

Primordial dwarfism-immunodeficiency-lipodystrophy syndrome (PDIL) is characterized by pre- and postnatal growth restriction, with extreme microcephaly, short stature, and absence of subcutaneous fat. There is also significant hematologic/immune dysfunction, with hypo- or agammaglobulinemia, as well as lymphopenia, anemia, and thrombocytopenia, and most affected individuals succumb to infection in early childhood (Parry et al., 2020).

Digenic dyskeratosis congenita (DKCD) is characterized clinically by a combination of mucocutaneous features including abnormal skin pigmentation, nail dystrophy, thin hair, and oral leukoplakia. Some patients may have evidence of bone marrow failure, manifest as immune defects such as recurrent infections or hypogammaglobulinemia. Telomeres are shortened in patient cells. Individuals with DKCD may show severe adverse reactions to treatment with 5-FU (Tummala et al., 2022). For a discussion of genetic heterogeneity of dyskeratosis congenita, see DKCA1 (127550).

Neurodevelopmental disorder with dysmorphic facies and ischiopubic hypoplasia (NEDFIH) is an autosomal recessive disorder characterized by these features and moderate to severe global developmental delay. Affected individuals show episodic regression during periods of stress, including seizures or infection, the latter of which may be associated with lymphopenia. Brain imaging shows diminished white matter volume, enlarged ventricles, and thin corpus callosum (Muffels et al., 2023).

Systemic autoinflammatory disease with vasculitis (SAIDV) is an autosomal dominant disorder that manifests soon after birth with features such as purpuric skin rash, fever, hepatosplenomegaly, and elevated C-reactive protein (CRP; 123260). Laboratory studies may show leukocytosis, thrombocytopenia, and autoantibodies. A subset of patients develop progressive liver involvement that may result in fibrosis. Other systemic features, such as periorbital edema, conjunctivitis, infections, abdominal pain, and arthralgia are usually observed. Mutations occur de novo. De Jesus et al. (2023) referred to this disorder as LAVLI (LYN kinase-associated vasculopathy and liver fibrosis).

Infantile-onset multisystem autoimmune disease-3 (ADMIO3) is an autosomal recessive disorder of immune dysregulation characterized by the onset of various systemic autoimmune manifestations in the first months or years of life. Features may include hypothyroidism, type 1 diabetes mellitus, systemic inflammatory manifestations (fever, hepatomegaly), and autoimmune cytopenias. Laboratory studies show normal levels of T, B, and NK cells, but CD4+ (see 186940) T cells demonstrate hyperproliferation when stimulated in vitro (Janssen et al., 2022). For a discussion of genetic heterogeneity of ADMIO, see ADMIO1 (615952).

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).