PAPA syndrome
Rare genetic disorder affecting skin and joints.
PAPA syndrome is a rare genetic condition that primarily affects the skin and joints. Its name comes from the initials of its three main features: pyogenic arthritis, pyoderma gangrenosum, and acne.
The arthritis usually appears in childhood and tends to be destructive. It often flares up after an injury, and repeated episodes can lead to joint damage severe enough to require multiple joint replacements. With better treatments now available, this damage may be less severe in newly diagnosed cases. Pyoderma gangrenosum does not affect everyone with the syndrome; when it does, it shows up as slow-healing ulcers with raised, ragged edges. A key feature is pathergy, meaning ulcers tend to form at sites of injury—for example, after a joint replacement surgery, a central line insertion, or an IV drip. Acne is common but varies in severity; when present, it is usually the severe nodulocystic type, which can cause scarring if left untreated.
The disorder follows an autosomal dominant inheritance pattern. If one parent is affected and homozygous for the mutation, every child will inherit the condition; if the parent is heterozygous, each child has a 50% chance. The responsible gene lies on chromosome 15, and two mutations have been found in a protein called CD2 binding protein 1 (CD2BP1). This protein is involved in an inflammatory pathway linked to other autoinflammatory diseases, such as familial Mediterranean fever, hyperimmunoglobulinemia D with recurrent fever, Muckle–Wells syndrome, neonatal onset multisystem inflammatory disease, and familial cold urticaria.
Diagnosis is often based on the combination of clinical features and a family history of the condition. Genetic testing can also be used to confirm it.
For acne, treatment may include oral tetracycline antibiotics or isotretinoin. For stubborn cases of arthritis or pyoderma gangrenosum, drugs that target tumor necrosis factor (like infliximab or etanercept) or interleukin-1 (like anakinra) have shown good results. Other traditional immunosuppressant medications for arthritis or pyoderma gangrenosum may also be used.
- Type
- Genetic disorder
- Acronym
- Pyogenic arthritis, pyoderma gangrenosum, acne
- Inheritance
- Autosomal dominant
- Gene location
- Chromosome 15
- Associated protein
- CD2 binding protein 1 (CD2BP1)
- Key features
- Arthritis, pyoderma gangrenosum, acne
Lore & Background
PAPA syndrome usually begins with arthritis at a young age, with skin changes becoming more prominent from puberty. The arthritis is the predominant feature, noted for its juvenile onset and destructive course. Individuals often recall episodes of arthritis precipitated by a traumatic event, and with repeated episodes, joints become damaged, requiring multiple joint replacements. Pyoderma gangrenosum is variably expressed, presenting as poorly healing ulcers with undermined edges. Pathergy is an important feature, meaning ulcers tend to arise at points of injury, including at the site of joint replacement wounds, central venous lines, and intravenous drip insertions. Acne affects most individuals to a variable degree, usually of a severe nodulocystic type that results in scarring if untreated.
Reader's Guide
PAPA syndrome is significant as a rare autoinflammatory disorder linking skin and joint pathology. Its genetic basis, with mutations in CD2BP1 on chromosome 15, places it within a family of autoinflammatory diseases including familial Mediterranean fever and Muckle–Wells syndrome. The condition's autosomal dominant inheritance pattern means affected individuals have a 50% chance of passing it to offspring if heterozygous, or 100% if homozygous. Diagnosis relies on clinical features and familial tendency, with genetic testing available. Treatment advances include biologics targeting tumor necrosis factor (infliximab, etanercept) and interleukin-1 (anakinra), which have shown good response in resistant arthritis and pyoderma gangrenosum, alongside traditional immunosuppressants and acne therapies like tetracycline antibiotics or isotretinoin. The destructive arthritis often leads to multiple joint replacements, but improved treatment options may limit damage in new cases.
Did You Know?
- PAPA syndrome is inherited in an autosomal dominant fashion.
- The responsible gene is located on chromosome 15, with mutations in CD2 binding protein 1.
- Pathergy, the tendency of ulcers to arise at points of injury, is an important feature of the syndrome.
- Treatments directed at tumor necrosis factor and interleukin-1 have shown good response in resistant arthritis and pyoderma gangrenosum.
More in Autoinflammatory syndromes 1-24
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