Mevalonate kinase deficiency is a condition characterized by recurrent episodes of fever, which typically begin during infancy. Each episode of fever lasts about 3 to 6 days, and the frequency of the episodes varies among affected individuals. In childhood the fevers seem to be more frequent, occurring as often as 25 times a year, but as the individual gets older the episodes occur less often.\n\nMevalonate kinase deficiency has additional signs and symptoms, and the severity depends on the type of the condition. There are two types of mevalonate kinase deficiency: a less severe type called hyperimmunoglobulinemia D syndrome (HIDS) and a more severe type called mevalonic aciduria (MVA).\n\nDuring episodes of fever, people with HIDS typically have enlargement of the lymph nodes (lymphadenopathy), abdominal pain, joint pain, diarrhea, skin rashes, and headache. Occasionally they will have painful sores called aphthous ulcers around their mouth. In females, these may also occur around the vagina. Rarely, people with HIDS develop a buildup of protein deposits (amyloidosis) in the kidneys that can lead to kidney failure. Fever episodes in individuals with HIDS can be triggered by vaccinations, surgery, injury, or stress. Most people with HIDS have abnormally high levels of immune system proteins called immunoglobulin D (IgD) and immunoglobulin A (IgA) in the blood. It is unclear why some people with HIDS have high levels of IgD and IgA and some do not. Elevated levels of these immunoglobulins do not appear to cause any signs or symptoms. Individuals with HIDS do not have any signs and symptoms of the condition between fever episodes and typically have a normal life expectancy.\n\nPeople with MVA have signs and symptoms of the condition at all times, not just during episodes of fever. Affected children have developmental delay, problems with movement and balance (ataxia), recurrent seizures (epilepsy), progressive problems with vision, and failure to gain weight and grow at the expected rate (failure to thrive). Individuals with MVA typically have an unusually small, elongated head. In childhood or adolescence, affected individuals may develop eye problems such as inflammation of the eye (uveitis), a blue tint in the white part of the eye (blue sclera), an eye disorder called retinitis pigmentosa that causes vision loss, or clouding of the lens of the eye (cataracts). Affected adults may have short stature and may develop muscle weakness (myopathy) later in life. During fever episodes, people with MVA may have an enlarged liver and spleen (hepatosplenomegaly), lymphadenopathy, abdominal pain, diarrhea, and skin rashes. Children with MVA who are severely affected with multiple problems may live only into early childhood; mildly affected individuals may have a normal life expectancy.

Ectodermal dysplasia with immunodeficiency-1 (EDAID1) is an X-linked recessive disorder that characteristically affects only males. Affected individuals have onset of recurrent severe infections due to immunodeficiency in early infancy or in the first years of life. There is increased susceptibility to bacterial, pneumococcal, mycobacterial, and fungal infections. Laboratory studies usually show dysgammaglobulinemia with low IgG subsets and normal or increased IgA and IgM, consistent with impaired 'class-switching' of B cells, although immunologic abnormalities may be subtle compared to the clinical picture, and B- and T-cell numbers are usually normal. There is a poor antibody response to polysaccharide vaccinations, particularly pneumococcus; response to other vaccinations is variable. Patients also have features of ectodermal dysplasia, including conical incisors, hypo/anhidrosis, and thin skin or hair. Severely affected individuals may also show lymphedema, osteopetrosis, and, rarely, hematologic abnormalities. The phenotype is highly variable, likely due to different hypomorphic mutations, and may be fatal in childhood. Intravenous immunoglobulins and prophylactic antibiotics are used as treatment; some patients may benefit from bone marrow transplantation. Although only males tend to be affected with immunodeficiency, many patients inherit a mutation from a mother who has mild features of IP or conical teeth (summary by Doffinger et al., 2001, Orange et al., 2004, Roberts et al., 2010, Heller et al., 2020). Genetic Heterogeneity of Ectodermal Dysplasia and Immune Deficiency Also see EDAID2 (612132), caused by mutation in the NFKBIA gene (164008).

Immunodeficiency-110 (IMD110) is an autosomal recessive primary T-cell immunodeficiency syndrome characterized by progressive loss of naive T cells, recurrent bacterial, viral, and fungal infections, warts, and abscesses, and autoimmune manifestations. Patients are at risk for developing lymphoproliferative disorders or lymphoma, particularly associated with EBV. Some patients may show cardiac malformations, including atrial septal defect (Abdollahpour et al., 2012; Nehme et al., 2012).

IMD23 is an autosomal recessive primary immunodeficiency syndrome characterized by onset of recurrent infections, usually respiratory or cutaneous, in early childhood. Immune workup usually shows neutropenia, lymphopenia, eosinophilia, and increased serum IgE or IgA. Neutrophil chemotactic defects have also been reported. Infectious agents include bacteria, viruses, and fungi. Many patients develop atopic dermatitis, eczema, and other signs of autoinflammation. Affected individuals may also show developmental delay or cognitive impairment of varying severity (summary by Bjorksten and Lundmark, 1976 and Zhang et al., 2014).

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-58 is an autosomal recessive primary immunologic disorder characterized by early-onset skin lesions, including eczematous dermatitis, infectious abscesses, and warts, recurrent respiratory infections or allergies, and chronic persistent infections with candida, Molluscum contagiosum, mycobacteria, EBV, bacteria, and viruses. Some patients may have gastrointestinal involvement, including inflammatory bowel disease, EBV+ smooth muscle tumors, and esophagitis. Immunologic analysis shows defective T-cell function with decreased Treg cells and deficient CD3/CD28 costimulation responses in both CD4+ and CD8+ T cells. B-cell function may also be impaired (summary by Wang et al., 2016 and Alazami et al., 2018).

Immunodeficiency-72 with autoinflammation and lymphoproliferation (IMD72) is an autosomal recessive immunologic disorder characterized by onset of recurrent infections or systemic inflammation in the first year of life. Affected individuals develop bacterial and viral infections that can be severe, including bacteremia, recurrent pneumonia, and meningitis, consistent with an immunodeficiency. There is also an autoimmune and hyperinflammatory aspect to the disorder, manifest as atopy or allergies, hepatosplenomegaly, and lymphoproliferation, including hemophagocytic lymphohistiocytosis (HLH). Immunologic workup shows variable abnormalities, including low or high Ig subsets, increased B cells, irregular T-cell activation and cytokine response, impaired immune synapse formation, and defective cellular migration. At the cellular level, these defects are related to abnormal F-actin polymerization and altered intracellular signaling (summary by Cook et al., 2020).