Neurofibromatosis type 2 (NF2) is a disorder characterized by the growth of noncancerous tumors of the nervous system. Childhood symptoms include skin growths and eye findings. Almost all people with NF2 develop vestibular schwannomas affecting both ears by age 30. Other tumors of the central nervous system (the brain and spinal cord), skin and eye are also…

Facioscapulohumeral muscular dystrophy is a disorder characterized by muscle weakness and wasting (atrophy). This condition gets its name from the areas of the body that are affected most often: muscles in the face (facio-), around the shoulder blades (scapulo-), and in the upper arms (humeral). The signs and symptoms of facioscapulohumeral muscular dystrophy usually appear…

Fetal and neonatal alloimmune thrombocytopenia (NAIT) is a blood disorder that affects pregnant women and their babies.[1] NAIT was first reported in the literature in 1953 and is estimated to occur in as many as 1 in 1200 live births.[2] NAIT results in the destruction of platelets in the fetus or infant due to a…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 36234 Definition Bacterial 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…

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…

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder that leads to the premature death and impaired production of blood cells. It can occur at any age, but is usually diagnosed in young adulthood. People with PNH have recurring episodes of symptoms due to hemolysis, which may be triggered by stresses on the body such as…

Retinitis pigmentosa (RP) is a group of inherited eye diseases that affect the light-sensitive part of the eye (retina). RP causes cells in the retina to die, causing progressive vision loss. The first sign of RP usually is night blindness. As the condition progresses, affected individuals develop tunnel vision (loss of peripheral vision), and eventually…

Chromosome 18p tetrasomy is a chromosomal disorder that affects many parts of the body. It occurs when the short arm of chromosome 18 (18p) appears four times (tetrasomy) rather than the normal two times in cells of the body.[1][2] The symptoms of chromosomy 18p tetrasomy vary from case to case but may include abnormalities of the head…

Oculopharyngeal muscular dystrophy (OPMD) is a genetic disorder characterized by slowly progressing muscle disease (myopathy) affecting the muscles of the upper eyelids and the throat. Onset is typically during adulthood, most often between 40 and 60 years of age. Symptoms may include: eyelid drooping (ptosis), arm and leg weakness, and difficulty swallowing (dysphagia).[1] There are two types…

Ovarian cancer is a form of cancer that occurs due to abnormal and uncontrolled cell growth in the ovaries. Many people with early ovarian cancer have no signs or symptoms of the condition. When present, symptoms are often nonspecific and blamed on other, more common conditions. Most cases of ovarian cancer occur sporadically in people…

Usher syndrome is a genetic disorder characterized by sensorineural hearing loss or deafness and progressive vision loss due to retinitis pigmentosa. Sensorineural hearing means it is caused by abnormalities of the inner ear. Retinitis pigmentosa is an eye disease that affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 331206 Definition Severe combined immunodeficiency due to complete RAG1/2 deficiency is a rare, genetic T-Bsevere combined immunodeficiency disorder due to null mutations in recombination activating gene (RAG) 1 and/or RAG2 resulting in less than 1%…

Hypochondroplasia is a form of skeletal disease characterized by very short stature. Hypochondroplasia is similar to achondroplasia, but the features tend to be milder. People with hypochondroplasia usually have very short stature, large head, accentuated lordosis, short arms and legs, and broad, short hands and feet. Other features include a limited range of motion in…

Cystinosis is a genetic condition present from birth that leads to the build-up of cystine crystals in the body. This can impact all the organs and tissues, but mainly affects the kidneys and eyes. There are three types of cystinosis based on the age that symptoms start. The most common is the type that starts…

ADNP syndrome, also known as Helsmoortel-van der Aa syndrome, is a complex neuro-developmental disorder that affects the brain and many other areas and functions of the body. ADNP syndrome can affect muscle tone, feeding, growth, hearing, vision, sleep, fine and gross motor skills, as well as the immune system, heart, endocrine system, and gastrointestinal tract.[1]…

Syringomyelia is a condition in which a cyst, called a syrinx, forms within the spinal cord. This cyst expands and elongates over time, destroying the center of the spinal cord which can result in pain, weakness, stiffness in the back, shoulders, arms, or legs, headaches, and insensitivity to temperature (especially in the hands). Symptoms vary…

Early-onset, autosomal dominant Alzheimer disease is a form of Alzheimer disease (AD) that develops before the age of 65. It is diagnosed in families that have more than one member with AD (usually multiple persons in more than one generation) in which the age of onset is consistently before age 60 and often between the ages…

Hereditary fructose intolerance (HFI) is a metabolic disease caused by the absence of an enzyme called aldolase B. In people with HFI, ingestion of fructose (fruit sugar) and sucrose (cane or beet sugar, table sugar) causes severe hypoglycemia (low blood sugar) and the build up of dangerous substances in the liver. HFI may be relatively mild or a…

Alpha mannosidosis  is a lysosomal storage disorder, a form of inborn metabolic disease. It is characterized by intellectual disability, hearing loss, ataxia, skeletal abnormalities, and coarse facial features.Signs and symptoms vary, but often include mild to moderate intellectual disability, hearing loss, weakened immune system, distinctive facial features, and cerebellar disorders (e.g., ataxia). Symptoms slowly worsen over time….

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,…

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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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…

Usher syndrome is a genetic disorder characterized by sensorineural hearing loss or deafness and progressive vision loss due to retinitis pigmentosa. Sensorineural hearing means it is caused by abnormalities of the inner ear. Retinitis pigmentosa is an eye disease that affects the layer of light-sensitive tissue at the back of the eye (the retina). Vision loss…

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: 517 Definition A rare acute myeloid leukemia disorder characterized by increased blast cells (myeloblasts, monoblast, and/or promonoblasts), representing more than 20% of the total bone marrow (BM) or peripheral blood differential counts, with 20-80% of…

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…

Alopecia universalis (AU) is a condition characterized by the complete loss of hair on the scalp and body. It is an advanced form of alopecia areata, a condition that causes round patches of hair loss.[1] Although the exact cause of AU is unknown, it is thought to be an autoimmune condition in which the person’s…

Mucopolysaccharidosis type I (MPS I) is a condition that affects many parts of the body. It is a progressively debilitating disorder; however, the rate of progression varies among affected individuals. MPS I is caused by mutations in the IDUA gene. These mutations lead to reduced levels or the complete lack of the IDUA enzyme. Without the proper amount…

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…

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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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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Alpha-1 antitrypsin deficiency (AATD) is an inherited disease that causes an increased risk of having chronic obstructive pulmonary disease (COPD), liver disease, skin problems (panniculitis), and inflammation of the blood vessels (vasculitis).[1][2][3] Lung (pulmonary) problems almost always occur in adults, whereas liver and skin problems may occur in adults and children.[2] The age symptoms begin and severity…

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…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 514 Definition Acute monoblastic leukemia (AML-M5), is one of the most common subtypes of acute myeloid leukemia (AML; see this term) that is either comprised of more than 80% of monoblasts (AML-M5a) or 30-80% monoblasts…

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a group of genetic kidney diseases that cause progressive loss of kidney function. Signs and symptoms of all forms of ADTKD include slowly worsening kidney disease (often becoming apparent by the teenage years) that ultimately results in end-stage kidney disease at some time between the ages of 20 and…

Supravalvular aortic stenosis (SVAS) is a type of heart defect that develops before birth. It is characterized by a narrowing (stenosis) of the section of the aorta just above the valve that connects the aorta to the heart (aortic valve). The severity of SVAS varies from person to person; some individuals may die in infancy…

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,…

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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Acquired hemophilia is a bleeding disorder that interferes with the body’s blood clotting process. Although the condition can affect people of all ages, it generally occurs in older people (the median age of diagnosis is between 60 and 67 years). Signs and symptoms include prolonged bleeding, frequent nosebleeds, bruising throughout the body, solid swellings of…

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…

X-linked adrenoleukodystrophy (X-ALD) is a genetic disease that affects the nervous system and the adrenal glands (small glands located on top of each kidney). People with this disease often have progressive loss of the fatty covering (myelin) that surrounds the nerves in the brain and spinal cord. They may also have a shortage of certain…

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…

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…

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,…

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…

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…

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…

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…

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…

Primary biliary cholangitis (PBC) is a chronic, progressive liver disease in which the bile ducts become inflamed and damaged.[1][2][3] This leads to the buildup of bile and causes liver problems such as scarring, cirrhosis (scarring and poor liver function), and eventual liver failure.[1] PBC is more common in women.[1][3][4] Many people do not have symptoms when…

Fuchs heterochromic iridocyclitis (FHI) is an unusual form of chronic (long-lasting) uveitis. Uveitis is swelling and irritation of the middle layer of the eye. Diagnosis of FHI is considered in people with floaters, vision loss, and heterochromia. FHI often affects young adults and most often involves a single eye. People with FHI are at risk…

Bardet-Biedl syndrome (BBS) is an inherited condition that affects many parts of the body. People with this syndrome have progressive visual impairment due to cone-rod dystrophy; extra fingers or toes (polydactyly); truncal obesity; decreased function of the male gonads (hypogonadism); kidney abnormalities; and learning difficulties.[1] Mutations in many genes are known to cause Bardet-Biedl syndrome and inheritance is…

Limb-girdle muscular dystrophy type 2B (LGMD2B) is one type of limb-girdle muscular dystrophy. These diseases affect the voluntary muscles, which are the muscles that are moved on purpose, such as the arms, legs, fingers, toes, and facial muscles. Specifically, LGMD2B is a slowly progressive disease that causes muscle weakness and wasting (atrophy) of the pelvic…

Sotos syndrome is a condition characterized mainly by distinctive facial features; overgrowth in childhood; and learning disabilities or delayed development. Facial features may include a long, narrow face; a high forehead; flushed (reddened) cheeks; a small, pointed chin; and down-slanting palpebral fissures. Affected infants and children tend to grow quickly; they are significantly taller than…

Congenital myasthenic syndromes (CMS) are a group of genetic conditions that all include muscle weakness that gets worse with physical activity. [1][2][3][4] There are many subtypes of CMS with different symptoms, severity, and treatments. Most people with CMS develop symptoms in infancy or by early childhood, but the age at which symptoms begin can vary. Symptoms…

Congenital fibrosis of extraocular muscles (CFEOM) refers to a group of rare conditions that affect the normal development and function of the muscles that control eye movement and position. In general, people affected by these conditions are unable to move their eyes in certain directions and often have strabismus and/or droopy eyelids (ptosis); however, the severity…

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…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 404 Definition Familial hyperaldosteronism type II (FH-II) is a heritable form of primary aldosteronism (PA) characterized by hypertension of varying severity, and non glucocticoid remediable hyperaldosteronism. Epidemiology PA is the most common form of secondary…

Gastrointestinal stromal tumors (GIST) are a type of soft tissue tumor that usually begin in specialized nerve cells in the wall of the stomach, intestines, or rectum, known as interstitial cells of Cajal. GIST may be noncancerous (benign) or cancerous (malignant). If cancerous, the tumor may also be called a soft tissue sarcoma. Symptoms depend on the location,…

Langerhans cell histiocytosis (LCH) is a disorder that primarily affects children, but is also found in adults of all ages. People with LCH produce too many Langerhans cells or histiocytes, a form of white blood cell found in healthy people that is supposed to protect the body from infection. In people with LCH, these cells multiply excessively and build up…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 93473 Definition Hurler syndrome is the most severe form of mucopolysaccharidosis type 1 (MPS1; see this term), a rare lysosomal storage disease, characterized by skeletal abnormalities, cognitive impairment, heart disease, respiratory problems, enlarged liver and…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 119 Definition A subtype of autosomal recessive limb girdle muscular dystrophy characterized by a childhood to adolescent onset of progressive pelvicand shoulder-girdle muscle weakness, particularly affecting the pelvic girdle (adductors and flexors of hip). Usually…