Rheumatoid arthritis is an inflammatory disease, primarily of the joints, with autoimmune features and a complex genetic component.

Muckle-Wells syndrome (MWS) is characterized by episodic skin rash, arthralgias, and fever associated with late-onset sensorineural deafness and renal amyloidosis (Dode et al., 2002).

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.

Familial periodic fever (FPF) is an autoinflammatory disorder characterized by recurrent fever with localized myalgia and painful erythema. Febrile attacks may last 1 or 2 days but often last longer than 1 week. Arthralgia of large joints, abdominal pain, conjunctivitis, and periorbital edema are common features. During attacks, painless cutaneous lesions may develop on the trunk or extremities and may migrate distally (review by Drenth and van der Meer, 2001).

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.

Infantile-onset multisystem autoimmune disease-1 is characterized by early childhood onset of a spectrum of autoimmune disorders affecting multiple organs. Common manifestations include insulin-dependent diabetes mellitus and autoimmune enteropathy, or celiac disease, and autoimmune hematologic disorders. Other features include short stature and nonspecific dermatitis. More variable features include hypothyroidism, autoimmune arthritis, and delayed puberty. Some patients may show recurrent infections. The disorder results from an inborn error of cytokine signaling (summary by Flanagan et al., 2014 and Milner et al., 2015). Genetic Heterogeneity of Infantile-Onset Multisystem Autoimmune Disease See also ADMIO2 (617006), caused by mutation in the ZAP70 gene (176947) on chromosome 2q12, and ADMIO3 (620430), caused by mutation in the CBLB gene (604491) on chromosome 3q13.

Familial Behcet-like autoinflammatory syndrome-1 (AIFBL1) is an autosomal dominant monogenic autoinflammatory disease characterized predominantly by painful and recurrent mucosal ulceration affecting the oral mucosa, gastrointestinal tract, and genital areas. The onset of symptoms is usually in the first decade, although later onset has been reported. Additional more variable features include skin rash, uveitis, and polyarthritis, consistent with a systemic hyperinflammatory state. Many patients have evidence of autoimmune disease. Rare patients may also have concurrent features of immunodeficiency, including recurrent infections with low numbers of certain white blood cells or impaired function of immune cells. The disorder results from a failure of mutant TNFAIP3 to suppress the activation of inflammatory cytokines in the NFKB (see 164011) signaling pathway; treatment with tumor necrosis factor (TNFA; 191160) inhibitors may be beneficial. Although some of the clinical features of AIFBL1 resemble those of Behcet disease (109650), the more common form of Behcet disease is believed to be polygenic, typically shows later onset in early adulthood, and has symptoms usually restricted to the mucosa (summary by Zhou et al., 2016; Aeschlimann et al., 2018, and Kadowaki et al., 2018). Genetic Heterogeneity of AIFBL See also AIFBL2 (301074), caused by mutation in the ELF4 gene (300775) on chromosome Xq26, and AIFBL3 (618287), caused by mutation in the RELA gene (164014) on chromosome 11q13.

Autoinflammation with arthritis and dyskeratosis (AIADK) is characterized by recurrent fever, widespread skin dyskeratosis, arthritis, elevated biologic markers of inflammation, and mild autoimmunity with a high transitional B-cell level (summary by Grandemange 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).

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).