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 kidney 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.

Cholestasis-lymphedema syndrome is a rare genetic disorder characterized by neonatal intrahepatic cholestasis, often lessening and becoming intermittent with age, and severe chronic lymphedema which mainly affects the lower limbs. Patients often present with fat malabsorption leading to failure to thrive, fat soluble vitamin deficiency with bleeding, rickets, and neuropathy. In 25% of cases, cirrhosis occurs during childhood or later in life.

TNF receptor-associated periodic fever syndrome (TRAPS) is characterized by episodes of inflammation typically occurring every four to six weeks and lasting between five and 25 days. Flares may be prompted by stress, infection, trauma, hormonal changes, and vaccination. Symptoms may include fever, abdominal pain, arthralgia, myalgia, migratory rash, and eye inflammation, with variable severity. Symptoms often begin in early childhood (median age 4.3 years), though symptom onset can occur later in life. During a flare, acute-phase reactants such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and serum amyloid A are typically elevated. Generally, acute-phase reactants stabilize between flares but may remain somewhat elevated even in the absence of clinical symptoms. AA amyloidosis, the most severe sequela of TRAPS, can largely be avoided with adequate treatment. Proteinuria and kidney failure occur in 80%-90% of affected individuals with amyloidosis, while intestinal, thyroid, myocardium, liver, and spleen deposits are less common.

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 kidney 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.

Hereditary fibrosing poikiloderma with tendon contractures, myopathy, and pulmonary fibrosis (POIKTMP) is characterized by the skin findings of poikiloderma (typically beginning in the first six months and mainly localized to the face), hypohidrosis with heat intolerance, mild lymphedema of the extremities, chronic erythematous and scaly skin lesions on the extremities, sclerosis of the digits, and mild palmoplantar keratoderma. Scalp hair, eyelashes, and/or eyebrows are typically sparse. Muscle contractures are usually seen in childhood and can be present as early as age two years. The majority of affected individuals develop progressive weakness of the proximal and distal muscles of all four limbs. Some adults develop progressive interstitial pulmonary fibrosis, which can be life threatening within three to four years after respiratory symptoms appear. Other features are exocrine pancreatic insufficiency, liver impairment, hematologic abnormalities, relative short stature, and cataract.

Hennekam lymphangiectasia-lymphedema syndrome (HKLLS1) is an autosomal recessive disorder characterized by generalized lymphatic dysplasia affecting various organs, including the intestinal tract, pericardium, and limbs. Additional features of the disorder include facial dysmorphism and cognitive impairment (summary by Alders et al., 2014). Genetic Heterogeneity of Hennekam Lymphangiectasia-Lymphedema Syndrome See also HKLLS2 (616006), caused by mutation in the FAT4 gene (612411) on chromosome 4q28, and HKLLS3 (618154), caused by mutation in the ADAMTS3 gene (605011) on chromosome 4q13.