The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.Orpha Number: 36234DefinitionBacterial toxic shock syndrome (TSS) is a potentially fatal, acute disease characterized by a sudden onset of high fever along with nausea, myalgia, vomiting and multisystem organ involvement, potentially leading to shock and death. TSS is…

Budd-Chiari syndrome is a rare disorder characterized by obstruction of the veins of the liver that carry the blood flow from the liver.[1][2] When the blood flow out of the liver is impeded, blood backs up in the liver, causing it to enlarge (hepatomegaly). The spleen may also enlarge (splenomegaly). This backup of blood increases blood…

Peutz-Jeghers syndrome (PJS) is an inherited condition that is associated with an increased risk of growths along the lining of the gastrointestinal tract (called hamartomatous polyps) and certain types of cancer. Most affected people also have characteristic dark blue to dark brown macules around the mouth, eyes, and nostrils; near the anus (perianal); and on…

Crouzon syndrome is a disorder characterized by early fusion of certain skull bones (craniosynostosis). This prevents normal growth of the skull, which can affect the shape of the head and face. Signs and symptoms of Crouzon syndrome may include wide-set, bulging eyes; strabismus (misalignment of the eyes); a small, “beak-shaped” nose; and an underdeveloped upper…

Progressive familial intrahepatic cholestasis type 3 (PFIC3) is a rare condition that affects the liver. People with this condition generally develop signs and symptoms during late infancy or early childhood, which may include severe itching, jaundice, failure to thrive, portal hypertension (high blood pressure in the vein that provides blood to the liver) and hepatosplenomegaly…

16p11.2 deletion syndrome is a condition caused by a missing piece (deletion) on a specific region of chromosome 16 designated as p11.2. People with 16p11.2 deletion syndrome usually have developmental delay and intellectual disability. Most also have at least some features of autism spectrum disorder. Some affected people have minor physical abnormalities; however, signs and…

Neurodegeneration with brain iron accumulation (NBIA) is a group of inherited neurologic disorders in which iron accumulates in the basal ganglia. Symptoms include progressive dystonia (a movement disorder resulting in muscular spasms, twisting, and repetitive movements) spasticity, parkinsonism (slurred or slow speech, stiffness of the muscles, slow movement, and visible tremors), inability to coordinate movements (ataxia),…

Pemphigus vulgaris is an autoimmune disorder that involves blistering and erosion of the skin and mucous membranes. It occurs almost exclusively in middle-aged or older people. The primary lesion of pemphigus vulgaris is a soft blister filled with clear fluid that appears on healthy or irritated skin. Many cases begin with blisters in the mouth, followed…

Pityriasis rubra pilaris (PRP) refers to a group of skin conditions that cause constant inflammation and scaling of the skin.[1] People with PRP have reddish, scaly patches that may occur everywhere on the body, or only on certain areas.[2][3] Some people with PRP also develop thickened skin on the underside of the hands and feet…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 70 Definition Proximal spinal muscular atrophies are a group of neuromuscular disorders characterized by progressive muscle weakness resulting from the degeneration and loss of the lower motor neurons in the spinal cord and the brain…

Dense deposit disease (DDD) is a condition that primarily affects kidney function. Signs and symptoms usually start between the ages of 5 and 15 but may also begin in adulthood. The major features of DDD are due to kidney malfunction, and often include proteinuria; hematuria; reduced amounts of urine; low levels of protein in the blood;…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 976 Definition A rare genetic nephropathy secondary to a disorder of purine metabolism characterized by the formation and hyperexcretion of 2,8-dihydroxyadenine (2,8-DHA) in urine, causing urolithiasis and crystalline nephropathy. Epidemiology Prevalence is estimated at 1/50,000…

McCune-Albright syndrome (MAS) is a disorder that affects the skin, skeleton, and certain endocrine organs (hormone-producing tissues). Cafe-au-lait spots of the skin are common and are usually the first apparent sign of MAS. The main skeletal feature is fibrous dysplasia, which ranges in severity and can cause various complications.[1] Early skeletal symptoms may include limping, pain, or…

Factor X deficiency is a rare disorder that affects the blood’s ability to clot. The severity of the disorder and the associated signs and symptoms can vary significantly from person to person. Common features of factor X deficiency may include easy bruising, frequent nosebleeds, bleeding gums, blood in the urine, and prolonged bleeding after minor…

Gitelman syndrome is a kidney function disorder that causes an imbalance of charged atoms (ions) in the body, including ions of potassium, magnesium, and calcium.[1] It is usually diagnosed during late childhood or adulthood.[2] More common symptoms include fatigue, salt craving, thirst, frequent urination, muscle cramping, muscle weakness, dizziness, tingling or numbness, low blood pressure,…

Autoimmune polyglandular syndrome type 1 is an inherited autoimmune condition that affects many of the body’s organs. Symptoms often begin in childhood or adolescence and may include mucocutaneous candidiasis, hypoparathyroidism, and Addison disease. This syndrome can cause a variety of additional signs and symptoms, such as weak teeth (enamel hypoplasia) and chronic diarrhea or constipation.[1] Also,…

Autosomal domiant spondyloepiphyseal dysplasia tarda (autosomal dominant SEDT) is an inherited condition that affects bone growth. Signs and symptoms are generally physically apparent by puberty; however, abnormalities may be seen on X-ray at an earlier age. Affected people may have skeletal abnormalities, short stature (with a short neck and trunk, specifically), scoliosis, kyphosis, lumbar hyperlordosis…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 70567 Definition Cholangiocarcinoma (CCA) is a biliary tract cancer (BTC, see this term) originating in the epithelium of the biliary tree, either intra or extra hepatic. Epidemiology The prevalence is unknown but it accounts for…

Hyperlipidemia type 3 is an inherited condition that disrupts the normal breakdown of fats (lipids) in the body, causing a large amount of certain fatty materials to build up in the body. Some individuals never have symptoms of this condition. Symptoms usually do not appear unless a second genetic or environmental factor adds to increased…

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Romano-Ward syndrome is the most common form of inherited long QT syndrome. Symptoms include arrhythmia, fainting, cardiac arrest, and sudden death. There are six different types of this syndrome, long QT 1 through 6. Each type is caused by a change in a different gene. The most prevalent form of long QT syndrome is long QT type 1. Long QT…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 75377 Definition Central areolar choroidal dystrophy (CACD) is a hereditary macular disorder, usually presenting between the ages of 30-60, characterized by a large area of atrophy in the centre of the macula and the loss…

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Congenital muscular dystrophy (CMD) refers to a group of inherited conditions that affect the muscles and are present at birth or in early infancy. The severity of the condition, the associated signs and symptoms and the disease progression vary significantly by type. Common features include hypotonia; progressive muscle weakness and degeneration (atrophy); joint contractures; and…

Prader-Willi syndrome (PWS) is a genetic condition that affects many parts of the body. Infants with PWS have severe hypotonia (low muscle tone), feeding difficulties, and slow growth. In later infancy or early childhood, affected children typically begin to eat excessively and become obese. Other signs and symptoms often include short stature, hypogonadism, developmental delays,…

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Neuromyelitis optica spectrum disorders (NMOSD) affect the spinal cord and optic nerves (nerves that carry visual messages to and from the brain). Symptoms include pain, weakness, bowel and bladder problems, and temporary vision loss. NMOSD usually occurs in adulthood, but symptoms may start at any age. Some people have a single attack of symptoms lasting months, but…

Congenital adrenal hyperplasia (CAH) due to 11-beta-hydroxylase deficiency is one of a group of disorders (collectively called congenital adrenal hyperplasia) that affect the adrenal glands. In this condition, the adrenal glands produce excess androgens (male sex hormones). This condition is caused by mutations in the CYP11B1 gene and is inherited in an autosomal recessive pattern. There are two…

Multiple endocrine neoplasia, type 1 (MEN1) causes the growth of tumors in both the endocrine system (the body’s network of hormone-producing glands) and non-endocrine system. Symptoms of MEN1 include tumors of the parathyroid gland, the pituitary gland, and the pancreas, although other glands may be involved as well. These tumors are often “functional” and secrete excess…

MYH9-related thrombocytopenia (MYH9RD) is a genetic condition caused by mutations in the MYH9 gene and is characterized by large platelets and thrombocytopenia (low number of platelets) which increases the risk for mild to serious bleeding in the body or in the skin. Young-adult onset high frequency sensorineural hearing loss, presenile (early) cataract, and kidney disease…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1146 Definition Digitotalar dysmorphism, also known as distal arthrogryposis type 1 (DA1), is an autosomal dominant congenital anomaly characterized by contractures of the distal regions of the hands and feet with no facial involvement or…

Mucopolysaccharidosis type IVA (MPS IVA, also called Morquio syndrome, type A) is a metabolic condition that primarily affects the skeleton. The severity, age of onset, and associated symptoms vary significantly from person to person and range from a severe and rapidly progressive, early-onset form to a slowly progressive, later-onset form. The severe form is usually…

Generalized pustular psoriasis is a severe inflammatory skin condition that can be life-threatening. Affected people develop episodes of red and tender skin with widespread pustules throughout their body. This is generally accompanied by fever, chills, headache, rapid pulse rate, loss of appetite, nausea and muscle weakness. The condition generally resolves within days or weeks; however,…

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Tuberous sclerosis complex (TSC) is characterized by the growth of benign tumors throughout the body, including in the heart, brain, and kidneys. Certain symptoms develop before to birth, such as heart tumors (rhabdomyoma). Other symptoms become more obvious in childhood, such as developmental delay and skin changes. Lung and kidney tumors are more likely to develop…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 79306 Definition PFIC1, a type of progressive familial intrahepathic cholestasis (PFIC, see this term), is an infantile hereditary disorder in bile formation that is hepatocellular in origin and associated with extrahepatic features. Epidemiology Estimated prevalence…

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Treacher Collins syndrome (TCS) is a condition that affects the development of bones and other tissues of the face. The signs and symptoms vary greatly, ranging from almost unnoticeable to severe. Most affected people have underdeveloped facial bones, particularly the cheek bones, and a very small jaw and chin (micrognathia). Other features may include cleft…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 616 Definition Medulloblastoma (MB) is an embryonic tumor of the neuroepithelial tissue and the most frequent primary pediatric solid malignancy. MB represents a heterogeneous group of cerebellar tumors characterized clinically by increased intracranial pressure and…

Mucopolysaccharidosis type IIIB (MPS IIIB) is an genetic disorder that makes the body unable to break down large sugar molecules called glycosaminoglycans (GAGs, formerly called mucopolysaccharides).[1][2] Specifically, people with this condition are unable to break down a GAG called heparan sulfate.[2] Affected individuals can have severe neurological symptoms, including progressive dementia, aggressive behavior, hyperactivity, seizures, deafness, loss…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 521 Definition Chronic myeloid leukaemia (CML) is the most common myeloproliferative disorder accounting for 15-20% of all leukaemia cases. Epidemiology Its annual incidence has been estimated at between 1 and 1.5 cases per 100,000 and…

Soft tissue sarcoma is a form of cancer that occurs due to abnormal and uncontrolled cell growth of the “soft tissues” of the body. These tissues connect, support and surround other body parts and may include muscle, fat, blood vessels, lymph vessels, nerves, tendons and the lining of joints. Many people with early soft tissue…

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Sideroblastic anemia pyridoxine-refractory autosomal recessive is an inherited blood disorder that is characterized by an impaired ability of the bone marrow to produce normal red blood cells. The iron inside red blood cells is inadequately used to make hemoglobin, despite adequate or increased amounts of iron. Abnormal red blood cells called sideroblasts are found in the…

Saethre-Chotzen syndrome is a genetic condition characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape and symmetry of the head and face. Other features may include webbing of certain fingers or toes (syndactyly), small or unusually shaped ears, short stature, and…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1203 Definition Duodenal atresia is an embryopathy of the cranial intestine that leads to a complete absence of the duodenal lumen. Epidemiology The incidence of duodenal atresia is between 1/10,000 and 1/6,000 live births, with…

Stargardt disease is a genetic eye disorder that causes progressive vision loss. It affects the macula, an area of the retina responsible for sharp, central vision. Vision loss is due to abnormal accumulation of a fatty yellow pigment (lipofuscin) in the cells within the macula. People with Stargardt disease also have problems with night vision,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 2023 Definition An aggressive sarcoma of soft tissues or bone that can arise from any part of the body, clinically presenting as swelling, mass, pain, pathological fracture and occasional systemic features and is characterized by…

Meningiomas are tumors that originate in the meninges, the membranes that surround the brain and spinal cord. Most meningiomas are not cancerous (benign), though a minority of meningiomas can be classified as atypical or cancerous (malignant).[1][2] Though rare, malignant meningiomas can be highly aggressive.[2] However, even benign meningiomas can cause problems if their growth affects neighboring…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 90793 Definition A very rare form of congenital adrenal hyperplasia (CAH) characterized by glucocorticoid deficiency, hypergonadotrophic hypogonadism and severe hypokalemic hypertension. Epidemiology It accounts for approximately 1% of all CAH cases. The prevalence is therefore…

Pycnodysostosis impacts bone growth and is present from birth. Symptoms include a large head and high forehead, undeveloped facial bones, and short fingers and toes. People with pycnodysostosis may have short stature, dental abnormalities, brittle bones, and delayed closure of the skull bones. Bones may become more brittle with age. Other complications like trouble breathing during…

Poland syndrome is characterized by an underdeveloped or absent chest muscle on one side of the body, absence of the breastbone portion (sternal) of the chest muscle, and webbing of the fingers of the hand on the same side. The cause of Poland syndrome is not known. This syndrome is nearly always sporadic. It tends to occur on the right side and…

Pseudoachondroplasia is an inherited disorder of bone growth which is characterized by short stature. Other features include short arms and legs, a waddling walk, early-onset joint pain (osteoarthritis), and a limited range of motion at the elbows and hips. Intelligence, facial features and head size are normal. Pseudoachondroplasia is caused by mutations in the COMP gene. This…

Cyclic neutropenia is a rare blood disorder characterized by recurrent episodes of abnormally low levels of neutrophils (a type of white blood cell) in the body. Neutrophils are instrumental in fighting off infection by surrounding and destroying bacteria that enter the body. Symptoms of cyclic neutropenia may include fever, a general feeling of ill health, and/or sores (ulcers)…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 99789 Definition Dentin dysplasia type I (DD-I) is a rare form of dentin dysplasia (DD, see this term) characterized by sharp conical short roots or rootless teeth. Epidemiology Prevalence of DD-I is reported to be…

Dermatofibrosarcoma protuberans is an uncommon cancer in which tumors arise in the deeper layers of skin. The tumor usually starts as a small, firm patch of skin; it may be purplish, reddish, or flesh-colored. It is commonly found on the torso, usually in the shoulder and chest area. The tumor typically grows slowly but has…

Sudden sensorineural deafness is a condition that is characterized by rapid, unexplained hearing loss. More specifically, affected people experience a reduction in hearing of greater than 30 decibels, which may occur all at once or over several days. In most cases, only one ear is affected. People with sudden sensorineural deafness often become dizzy, have…

Early-onset generalized dystonia is a neurologic movement disorder that usually begins in childhood or adolescence. This is the most common hereditary form of dystonia.[1] Symptoms start in one part of the body (usually an arm, foot, or leg) and are usually first apparent with actions such as writing or walking. With time, the contractions may spread…

Adult-onset Still’s disease (AOSD) is an inflammatory condition that affects multiple organs. The most common symptoms are high fevers, skin rash, arthritis, and high levels of ferritin, a protein that stores iron in the blood. Other symptoms include an enlarged spleen and lymph nodes, joint pain, and sore throat. In some cases, symptoms may be…

EEC syndrome (Ectrodactyly-Ectodermal DysplasiaCleft Lip/Palate) is a rare form of ectodermal dysplasia. The symptoms can vary from mild to severe and most commonly include missing or irregular fingers and/or toes (ectrodactyly or split hand/foot malformation); abnormalities of the hair and glands; cleft lip and/or palate; distinctive facial features; and abnormalities of the eyes and urinary…

Osteopetrosis refers to a group of rare, inherited skeletal disorders characterized by increased bone density and abnormal bone growth.[1][2] Symptoms and severity can vary greatly, ranging from neonatal onset with life-threatening complications (such as bone marrow failure) to the incidental finding of osteopetrosis on X-ray. Depending on severity and age of onset, features may include fractures, short stature,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 36899 Definition Myoclonusdystonia syndrome (MDS) is a rare movement disorder characterized by mild to moderate dystonia along with ‘lightning-like’ myoclonic jerks. Epidemiology The estimated prevalence of MDS in Europe is 1/500,000. Clinical description Disease onset…

Alpha-thalassemia is a blood disorder that reduces the body’s production of hemoglobin. Affected people have anemia, which can cause pale skin, weakness, fatigue, and more serious complications. Two types of alpha-thalassemia can cause health problems: the more severe type is known as Hb Bart syndrome; the milder form is called HbH disease. Hb Bart syndrome…

Hydrocephalus due to congenital stenosis of aqueduct of sylvius (HSAS) is a form of L1 syndrome, which is an inherited disorder that primarily affects the nervous system. Males with HSAS are typically born with severe hydrocephalus and adducted thumbs (bent towards the palm). Other sign and symptoms of the condition include severe intellectual disability and…

Cat scratch disease (CSD) is a bacterial infection that primarily affects the lymph nodes. It is typically caused by the bacteria bartonella (Bartonella henselae). It is usually transmitted by being scratched or bitten by a cat, but rarely, no scratch or bite is involved.[1] Symptoms frequently include the formation of a small bump at the site of…

A schwannoma is a tumor of the peripheral nervous system or nerve root. A schwannoma develops from cells called Schwann cells, a type of cell that wraps itself around peripheral nerves and provides protection and support. Schwannomas are almost always benign (not cancerous), but rarely, may become cancerous (a malignant schwannoma).[1][2] Symptoms of a schwannoma…

Osteogenesis imperfecta (OI) is a group of genetic disorders that mainly affect the bones. People with this condition have bones that break easily, often from little or no trauma, however, severity varies among affected people. Multiple fractures are common, and in severe cases, can even occur before birth. Milder cases may involve only a few…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 99842 Definition Leukocyte adhesion deficiency type I (LAD-I) is a form of LAD (see this term) characterized by life-threatening, recurrent bacterial infections. Epidemiology LAD-I affects 1 individual per million. Clinical description Usually the first signs…

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer. It usually develops as a single, painless, bump on sun-exposed skin. The bump may be skin-colored or red-violet, and tends to grow rapidly over weeks to months. It may spread quickly to surrounding tissues, nearby lymph nodes, or more distant parts of the body. Factors associated with…

Friedreich ataxia is an inherited condition that affects the nervous system and causes movement problems. People with this condition develop impaired muscle coordination (ataxia) that worsens over time. Other features include the gradual loss of strength and sensation in the arms and legs, muscle stiffness (spasticity), and impaired speech. Many individuals have a form of heart…

Ectodermal dysplasias (ED) are a group of more than 180 disorders that affect the outer layer of tissue of the embryo (ectoderm) that helps make up the skin, sweat glands, hair, teeth, and nails. Symptoms of ED can range from mild to severe and may include teeth abnormalities; brittle, sparse or absent hair; abnormal fingernails;…

Congenital adrenal hyperplasia (CAH) refers to a group of genetic conditions that affect the adrenal glands. These glands sit on top of the kidneys and are responsible for releasing various types of hormones that the body needs to function. Affected people lack an enzyme the adrenal glands need to make one or more of these…

Spinal muscular atrophy (SMA) is a group of genetic neuromuscular disorders that affect the nerve cells that control voluntary muscles (motor neurons). The loss of motor neurons causes progressive muscle weakness and loss of movement due to muscle wasting (atrophy). The severity of the symptoms, the age at which symptoms, begin, and genetic cause varies…

Rett syndrome is a progressive, neuro-developmental condition that primarily affects girls. Affected girls appear to have normal psychomotor development during the first 6 to 18 months of life, followed by a developmental “plateau,” and then rapid regression in language and motor skills. Additional signs and symptoms may include repetitive, stereotypic hand movements; fits of screaming…

Focal segmental glomerulosclerosis (FSGS) is a type of kidney disorder. It is characterized by scar tissue that forms in some of the glomeruli in the kidney.[1] FSGS may cause non-specific signs and symptoms, including protein in the urine, elevated levels of creatinine, and swelling.[2][3] In many cases the cause of FSGS can not be determined. Some…

Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by too few platelets in the blood. This is because platelets are being destroyed by the immune system. Symptoms may include bruising, nosebleed or bleeding in the mouth, bleeding into the skin, and abnormally heavy menstruation. With treatment, the chance of remission (a symptom-free period) is…

Lennox-Gastaut syndrome is a form of severe epilepsy that begins in childhood. It is characterized by multiple types of seizures and intellectual disability.[1] This condition can be caused by brain malformations, perinatal asphyxia (lack of oxygen), severe head injury, central nervous system infection and inherited degenerative or metabolic conditions. In about one-third of cases, no…

Autoimmune hemolytic anemia (AIHA) occurs when your immune system makes antibodies that attack your red blood cells. This causes a drop in the number of red blood cells, leading to hemolytic anemia.[1][2][3][4] Symptoms may include unusual weakness and fatigue with tachycardia and breathing difficulties, jaundice, dark urine and/or splenomegaly. AIHA can be primary (idiopathic) or result from…

IgA nephropathy is a kidney disorder that occurs when IgA (immunoglobulin A), a protein that helps the body fight infections, settles in the kidneys. IgA nephropathy can occur at any age, even in childhood. After many years, deposits of IgA may cause the kidneys to leak blood and sometimes protein in the urine. In the early…

Narcolepsy is a chronic brain disorder that involves poor control of sleep-wake cycles. People with narcolepsy have episodes of extreme daytime sleepiness and sudden, irresistible bouts of sleep (called “sleep attacks”) that can occur at any time, and may last from seconds or minutes. Other signs and symptoms may include cataplexy (a sudden loss of…