| STING-associated vasculopathy with onset in infancy | |
|---|---|
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| Autosomal dominant pattern is the inheritance manner of this condition | |
| Specialty | Medical genetics |
| Causes | Mutations in the TMEM173 gene |
STING-associated vasculopathy with onset in infancy (SAVI [1] ) is a rare autoinflammatory vasculopathy associated with the stimulator of interferon genes (STING) protein and characterised by severe skin lesions and interstitial lung disease.
The onset is in infancy. The skin lesions occur on cheeks, nose, fingers, toes and soles. [2] They may vary in appearance but frequently develop into non-healing ulcers. Interstitial lung disease is also common. Some individuals may not experience any obvious skin issues. All affected children fail to thrive.[ citation needed ]
Other features include myositis and joint stiffness. Some children experience hyper mobility, and joint pain.[ citation needed ]
Imaging:
Chest X-rays show sign consistent with interstitial lung disease.[ citation needed ]
Bloods:
Anemia, leukopenia, thrombocytosis, T cell lymphopenia with normal B cells and hypergammaglobulinemia may occur. [ citation needed ]
Autoantibodies may be present including antinuclear, antiphospholipid, and anticardiolipin antibodies.[ citation needed ]
The erythrocyte sedimentation rate and C reactive protein levels tend to be raised. [ citation needed ]
Biopsies:
Skin biopsies show inflammation of the capillaries and microthrombosis. Immunoglobulin M and C3 deposition may be present.[ citation needed ]
Lung biopsies show fibrosing alveolitis, follicular hyperplasia, B-cell germinal centers and interstitial fibrosis. Some children demonstrate pulmonary alveolar protianosis on Lavage.[ citation needed ]
This condition is due to mutations in the TMEM173 gene. This gene is located on the long arm of chromosome 5 (5q31.2) and encodes the stimulator of interferon genes (STING) protein. There are 3 disease causing mutations in the dimerization domain of STING that cause SAVI; V155M, N154S, and V147L.[ citation needed ]
This only partly understood. The wild type protein (STING) is normally found in the cytoplasm of the cell. The mutant forms are located in the Golgi apparatus.[ citation needed ]
The condition may be suspected on clinical grounds. The diagnosis is made by sequencing the TMEM173 gene.[ citation needed ]
No specific treatment is known. Management is supportive. Research into the efficacy of a subgroup of medications known as JAK inhibitors (such as Baricitinib) has been studied at the National Institutes of Health, starting in 2014.[ citation needed ]
This condition is considered rare, with 9 cases reported in the literature up to 2019.[ citation needed ]
This disease was first described in 2014. [3] In 2017 a group led by Dr. Jonathan Miner generated the first mouse model of SAVI. Dr. Miner's research team used CRISPR/Cas9 genome editing to introduce a mutation into the mouse STING gene (STING1) [4] that was analogous to a human SAVI-associated mutation. These mice, known as STING N153S or SAVI mice, developed spontaneous lung disease and a severe immunodeficiency to a herpesviruses. [5] SAVI mice also develop lung disease that depends on adaptive immunity, but not on the type I interferon receptor. [6] Whereas SAVI mice also lack lymph nodes and have reduced numbers of innate lymphoid cells (ILCs), patients with SAVI do have lymph nodes despite also having reduced numbers of ILCs. [7] Lung disease in SAVI mice also can be regulated by microbes, [8] which might reflect the capacity of STING to detect or be regulated by microbial metabolites. The Miner laboratory subsequently moved to the University of Pennsylvania (Penn), where research on mechanisms of STING-associated autoimmunity has continued. [9] Other laboratories including those of Kate Fitzgerald (UMass) and Angela Rosen-Wolff (TU Dresden), independently generated the same SAVI mice, as well as additional models, and made similar findings with regard to the role of type I interferon in the mouse model of SAVI. [10]
Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesodermal or ectodermal germ layer during embryogenesis.
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disease. The tissue is then fixed, dehydrated, embedded, sectioned, stained and mounted before it is generally examined under a microscope by a pathologist; it may also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. An incisional biopsy or core biopsy samples a portion of the abnormal tissue without attempting to remove the entire lesion or tumor. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy. Biopsies are most commonly performed for insight into possible cancerous or inflammatory conditions.
Pulmonary alveolar proteinosis (PAP) is a rare lung disorder characterized by an abnormal accumulation of surfactant-derived lipoprotein compounds within the alveoli of the lung. The accumulated substances interfere with the normal gas exchange and expansion of the lungs, ultimately leading to difficulty breathing and a predisposition to developing lung infections. The causes of PAP may be grouped into primary, secondary, and congenital causes, although the most common cause is a primary autoimmune condition in an individual.
Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye. In women, they most commonly occur on the legs, while in men, they most commonly occur on the back. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include an increase in size, irregular edges, change in color, itchiness, or skin breakdown.
Gunther disease is a congenital form of erythropoietic porphyria. The word porphyria originated from the Greek word porphura. Porphura actually means "purple pigment", which, in suggestion, the color that the body fluid changes when a person has Gunther's disease. It is a rare, autosomal recessive metabolic disorder affecting heme, caused by deficiency of the enzyme uroporphyrinogen cosynthetase. It is extremely rare, with a prevalence estimated at 1 in 1,000,000 or less. There have been times that prior to birth of a fetus, Gunther's disease has been shown to lead to anemia. In milder cases patients have not presented any symptoms until they have reached adulthood. In Gunther's disease, porphyrins are accumulated in the teeth and bones and an increased amount are seen in the plasma, bone marrow, feces, red blood cells, and urine.
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium of the lungs. It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage, but in interstitial lung disease, the repair process is disrupted, and the tissue around the air sacs (alveoli) becomes scarred and thickened. This makes it more difficult for oxygen to pass into the bloodstream. The disease presents itself with the following symptoms: shortness of breath, nonproductive coughing, fatigue, and weight loss, which tend to develop slowly, over several months. The average rate of survival for someone with this disease is between three and five years. The term ILD is used to distinguish these diseases from obstructive airways diseases.
Primary myelofibrosis (PMF) is a rare bone marrow blood cancer. It is classified by the World Health Organization (WHO) as a type of myeloproliferative neoplasm, a group of cancers in which there is growth of abnormal cells in the bone marrow. This is most often associated with a somatic mutation in the JAK2, CALR, or MPL gene markers. In PMF, the healthy marrow is replaced by scar tissue (fibrosis), resulting in a lack of production of normal blood cells. Symptoms include anemia, increased infection and an enlarged spleen (splenomegaly).
Lymphangioleiomyomatosis (LAM) is a rare, progressive and systemic disease that typically results in cystic lung destruction. It predominantly affects women, especially during childbearing years. The term sporadic LAM is used for patients with LAM not associated with tuberous sclerosis complex (TSC), while TSC-LAM refers to LAM that is associated with TSC.
Pulmonary fibrosis is a condition in which the lungs become scarred over time. Symptoms include shortness of breath, a dry cough, feeling tired, weight loss, and nail clubbing. Complications may include pulmonary hypertension, respiratory failure, pneumothorax, and lung cancer.
Polymyositis (PM) is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis. Its name means "inflammation of many muscles". The inflammation of polymyositis is mainly found in the endomysial layer of skeletal muscle, whereas dermatomyositis is characterized primarily by inflammation of the perimysial layer of skeletal muscles.
Langerhans cell histiocytosis (LCH) is an abnormal clonal proliferation of Langerhans cells, abnormal cells deriving from bone marrow and capable of migrating from skin to lymph nodes.
Non-small-cell lung carcinoma (NSCLC) is any type of epithelial lung cancer other than small-cell lung carcinoma (SCLC). NSCLC accounts for about 85% of all lung cancers. As a class, NSCLCs are relatively insensitive to chemotherapy, compared to small-cell carcinoma. When possible, they are primarily treated by surgical resection with curative intent, although chemotherapy has been used increasingly both preoperatively and postoperatively.
Idiopathic pulmonary fibrosis (IPF), or (formerly) fibrosing alveolitis, is a rare, progressive illness of the respiratory system, characterized by the thickening and stiffening of lung tissue, associated with the formation of scar tissue. It is a type of chronic scarring lung disease characterized by a progressive and irreversible decline in lung function. The tissue in the lungs becomes thick and stiff, which affects the tissue that surrounds the air sacs in the lungs. Symptoms typically include gradual onset of shortness of breath and a dry cough. Other changes may include feeling tired, and abnormally large and dome shaped finger and toenails. Complications may include pulmonary hypertension, heart failure, pneumonia or pulmonary embolism.
Tricho-hepato-enteric syndrome (THE), also known as syndromic or phenotypic diarrhea, is an extremely rare congenital bowel disorder which manifests itself as intractable diarrhea in infants with intrauterine growth retardation, hair and facial abnormalities. Many also have liver disease and abnormalities of the immune system. The associated malabsorption leads to malnutrition and failure to thrive.
Surfactant metabolism dysfunction is a condition where pulmonary surfactant is insufficient for adequate respiration. Surface tension at the liquid-air interphase in the alveoli makes the air sacs prone to collapsing post expiration. This is due to the fact that water molecules in the liquid-air surface of alveoli are more attracted to one another than they are to molecules in the air. For sphere-like structures like alveoli, water molecules line the inner walls of the air sacs and stick tightly together through hydrogen bonds. These intermolecular forces put great restraint on the inner walls of the air sac, tighten the surface all together, and unyielding to stretch for inhalation. Thus, without something to alleviate this surface tension, alveoli can collapse and cannot be filled up again. Surfactant is essential mixture that is released into the air-facing surface of inner walls of air sacs to lessen the strength of surface tension. This mixture inserts itself among water molecules and breaks up hydrogen bonds that hold the tension. Multiple lung diseases, like ISD or RDS, in newborns and late-onsets cases have been linked to dysfunction of surfactant metabolism.
Aicardi–Goutières syndrome (AGS), which is completely distinct from the similarly named Aicardi syndrome, is a rare, usually early onset childhood, inflammatory disorder most typically affecting the brain and the skin. The majority of affected individuals experience significant intellectual and physical problems, although this is not always the case. The clinical features of AGS can mimic those of in utero acquired infection, and some characteristics of the condition also overlap with the autoimmune disease systemic lupus erythematosus (SLE). Following an original description of eight cases in 1984, the condition was first referred to as 'Aicardi–Goutières syndrome' (AGS) in 1992, and the first international meeting on AGS was held in Pavia, Italy, in 2001.
Stimulator of interferon genes (STING), also known as transmembrane protein 173 (TMEM173) and MPYS/MITA/ERIS is a protein that in humans is encoded by the STING1 gene.
Granulomatous–lymphocytic interstitial lung disease (GLILD) is a lung complication of common variable immunodeficiency disorders (CVID). It is seen in approximately 15% of patients with CVID. It has been defined histologically as the presence of (non-caseating) granuloma and lymphoproliferation in the lung. However, as GLILD is often associated with other auto-immune features such as splenomegaly, adenopathy and cytopenias, a definition based on abnormalities on lung imaging together with evidence of granulomatous inflammation elsewhere has also been employed.
Idiopathic multicentric Castleman disease (iMCD) is a subtype of Castleman disease, a group of lymphoproliferative disorders characterized by lymph node enlargement, characteristic features on microscopic analysis of enlarged lymph node tissue, and a range of symptoms and clinical findings.
Pediatric-type follicular lymphoma (PTFL) is a disease in which malignant B-cells accumulate in, overcrowd, and cause the expansion of the lymphoid follicles in, and thereby enlargement of the lymph nodes in the head and neck regions and, less commonly, groin and armpit regions. The disease accounts for 1.5% to 2% of all the lymphomas that occur in the pediatric age group.