Familial Mediterranean fever (FMF) is divided into two phenotypes: type 1 and type 2. FMF type 1 is characterized by recurrent short episodes of inflammation and serositis including fever, peritonitis, synovitis, pleuritis, and, rarely, pericarditis and meningitis. The symptoms and severity vary among affected individuals, sometimes even among members of the same family. Amyloidosis, which can lead to renal failure, is the most severe complication, if untreated. FMF type 2 is characterized by amyloidosis as the first clinical manifestation of FMF in an otherwise asymptomatic individual.

A rare, genetic, chronic, recurrent, slowly progressive, epidermal disease characterized by small, sterile, pustular eruptions, involving the nails and surrounding skin of the fingers and/or toes, which coalesce and burst, leaving erythematous, atrophic skin where new pustules develop. Onychodystrophy is frequently associated and anonychia and osteolysis are reported in severe cases. Local expansion (to involve the hands, forearms and/or feet) and involvement of mucosal surfaces (e.g. conjunctiva, tongue, urethra) may be observed.

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.

Congenital disorder of glycosylation type IIc (CDG2C) is an autosomal recessive disorder characterized by moderate to severe psychomotor retardation, mild dysmorphism, and impaired neutrophil motility. It is a member of a group of disorders with a defect in the processing of protein-bound glycans. For a general overview of congenital disorders of glycosylation (CDGs), see CDG1A (212065) and CDG2A (212066). Frydman (1996) contended that the neutrophil defect in CDG2C, which has been referred to as 'leukocyte adhesion deficiency type II' (LAD2), is a manifestation of the disorder and that there are no cases of 'primary' LAD II. Etzioni and Harlan (1999) provided a comprehensive review of both leukocyte adhesion deficiency-1 (LAD1; 116920) and LAD2. While the functional neutrophil studies are similar in the 2 LADs, the clinical course is milder in LAD2. Furthermore, patients with LAD2 present other abnormal features, such as growth and mental retardation, which are related to the primary defect in fucose metabolism. Delayed separation of the umbilical cord occurs in LAD1. For a discussion of genetic heterogeneity of LAD, see 116920.

A rare, genetic, immune disease characterized by chronic neutrophilia, increase in the percentage of circulating CD34+ cells in peripheral blood, increase in granulocyte precursors in bone marrow and splenomegaly. Patients are predominantly asymptomatic, but may present with systemic inflammatory response syndrome with fever, dyspnea, tachycardia, pleural and pericardial effusion, or myelodysplastic syndrome.

Immunodeficiency-73A with defective neutrophil chemotaxis and leukocytosis (IMD73A) is an immunologic disorder characterized by onset of recurrent infections in early infancy. Affected infants have periumbilical erythema and later develop skin abscesses and invasive infections. Laboratory studies show leukocytosis, neutrophilia, decreased TRECs, and T-cell abnormalities. Neutrophils showed decreased chemotaxis associated with actin polymerization abnormalities, as well as variably impaired oxidative responses. Hematopoietic stem cell transplant may be curative (summary by Accetta et al., 2011; review by Lougaris et al., 2020). In a review of autosomal forms of chronic granulomatous disease (see 306400 for genetic heterogeneity of CGD), Roos et al. (2021) noted that patients with RAC2 mutations may manifest CGD-like symptoms due to defects in neutrophil NADPH oxidase activity.

Chronic recurrent multifocal osteomyelitis-2 with periostitis and pustulosis (CRMO2) is an autosomal recessive multisystemic autoinflammatory disorder characterized by onset of symptoms in early infancy. Affected individuals present with joint swelling and pain, pustular rash, oral mucosal lesions, and fetal distress. The disorder progresses in severity to generalized severe pustulosis or ichthyosiform lesions and diffuse bone lesions. Radiographic studies show widening of the anterior rib ends, periosteal elevation along multiple long bones, multifocal osteolytic lesions, heterotopic ossification, and metaphyseal erosions of the long bones. Laboratory studies show elevation of inflammatory markers. The disorder results from unopposed activation of the IL1 inflammatory signaling pathway. Treatment with the interleukin-1 receptor antagonist anakinra may result in clinical improvement (Aksentijevich et al., 2009). For a discussion of genetic heterogeneity of CRMO, see 609628.

Immunodeficiency-32B is an autosomal recessive primary immunodeficiency characterized by recurrent infections resulting from variable defects in immune cell development or function, including monocytes, dendritic cells, and natural killer (NK) cells. Patients have particular susceptibility to viral disease (summary by Mace et al., 2017).

Autoinflammation, panniculitis, and dermatosis syndrome (AIPDS) is an autosomal recessive autoinflammatory disease characterized by neonatal onset of recurrent fever, erythematous rash with painful nodules, painful joints, and lipodystrophy. Additional features may include diarrhea, increased serum C-reactive protein (CRP), leukocytosis, and neutrophilia in the absence of any infection. Patients exhibit no overt primary immunodeficiency (Damgaard et al., 2016 and Zhou et al., 2016).

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-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).

Immunodeficiency-113 with autoimmunity and autoinflammation (IMD113) is an autosomal recessive complex immunologic disorder with onset of symptoms in infancy. Affected individuals have recurrent infections and usually show features of autoimmunity and autoinflammation, such as hemolytic anemia, thrombocytopenia, hepatosplenomegaly, leukocytosis, neutrophilia, and elevated acute phase reactants. More variable systemic features may include celiac disease or enteropathy, ileus, nephropathy, eczema, and dermatomyositis. Additional features include facial dysmorphism, scoliosis, and poor wound healing. One patient with neurodevelopmental abnormalities has been reported. The disorder results from dysregulation of the actin cytoskeleton that affects certain cell lineages (Nunes-Santos et al., 2023).