Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease characterized by weakness of the skeletal muscles. Common symptoms include weakness of the muscles that control the eye and eyelid, facial expressions, chewing, talking, and swallowing. Weakness tends to increase during periods of activity and improve after periods of rest. The condition results from a defect in…

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a neurological disorder that causes progressive weakness and impaired sensory function in the legs and arms. Symptoms often include tingling or numbness (first in the toes and fingers), weakness of the arms and legs, loss of deep tendon reflexes, fatigue, and abnormal sensations.[1] Other symptoms may include pain, difficulty…

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…

Cystinuria is an inherited condition characterized by a buildup of the amino acid, cystine, in the kidneys and bladder. This leads to the formation of cystine crystals and/or stones which may block the urinary tract. Signs and symptoms of the condition are related to the presence of stones and may include nausea, hematuria, flank pain,…

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…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 79400 Definition Localized epidermolysis bullosa simplex, formerly known as EBS, Weber-Cockayne, is a basal subtype of epidermolysis bullosa simplex (EBS, see this term). The disease is characterized by blisters occurring mainly on the palms and…

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….

Sjogren-Larsson syndrome (SLS) is an inborn error of lipid metabolism, characterized by congenital ichthyosis (dry, scaly skin), intellectual disability, and spasticity (stiffness and involuntary muscle spasms). The syndrome is caused by mutations in the gene called FADH (fatty aldehyde dehydrogenase) and is inherited in an autosomal recessive fashion. Treatment is symptomatic.[1][2]

Pulmonary arterial hypertension (PAH) affects the heart and lungs. It is characterized by abnormally high blood pressure (hypertension) in the pulmonary artery, the blood vessel that carries blood from the heart to the lungs. Symptoms include shortness of breath (dyspnea) during exercise and fainting spells. The symptoms tend to get worse over time and may include dizziness, swelling…

Hereditary hemorrhagic telangiectasia (HHT) is an inherited disorder of the blood vessels that can cause excessive bleeding. People with HHT can develop abnormal blood vessels called arteriovenous malformations (AVMs) in several areas of the body. AVMs on the skin are called telangiectasias. AVMs can also develop in other parts of the body, including the brain, lungs,…

Tetrahydrobiopterin (BH4) deficiency causes the body to build up an abnormally high level of phenylalanine, one of the building blocks of proteins. In addition, BH4 deficiency leads to low levels of certain neurotransmitters, chemical messengers that control many body functions. Symptoms can range from very mild to severe. Babies with BH4 deficiency appear normal at birth…

Dermatitis herpetiformis is a rare, chronic, skin disorder characterized by groups of severely itchy blisters and raised skin lesions. These are more common on the knees, elbows, buttocks and shoulder blades. The slow onset of symptoms usually begins during adulthood, but children can also be affected. Other symptoms may include fluid-filled sores; red lesions that resemble hives;…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 251899 Definition Choroid plexus carcinoma is a rare and highly aggressive malignant type of choroid plexus tumor (see this term) occurring almost exclusively in children, presenting with cerebrospinal fluid obstruction in the lateral ventricles (most…

Neuroblastoma is a tumor that develops from neuroblasts (immature nerve tissue) in an infant or child, usually before the age of 5. It most often develops in infancy and may be diagnosed in the first month of life. The tumor most often develops in the adrenal gland, but may develop in the neck, chest, or…

Darier disease is a skin condition characterized by wart-like blemishes on the body. The blemishes are usually yellowish in color, hard to the touch, mildly greasy, and can emit a strong odor. The most common sites for blemishes are the scalp, forehead, upper arms, chest, back, knees, elbows, and behind the ear. The mucous membranes…

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…

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…

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…

empty

Spinocerebellar ataxia 3 (SCA3) is a rare, inherited form of ataxia. Signs and symptoms may begin between childhood and late adulthood and vary greatly. Symptoms may include slowly progressive clumsiness in the arms and legs; a manner of walking (gait) that may be mistaken for drunkenness; difficulty speaking and swallowing; impaired eye movements or vision; and lower…

Klatskin tumors are are a type of cholangiocarcinoma that begins in an area called the hilum, where the left and right bile ducts join and leave the liver. It is the most common type of cholangiocarcinoma, accounting for more than half of all cases.[1][2][3][4] Symptoms usually don’t present until advanced stages of disease, when jaundice…

Fukuyama type muscular dystrophy (FCMD) affects the muscles and brain, causing muscle damage that gets worse over time. There are mild, typical, and severe forms of FCMD. Symptoms begin at birth and include a poor suck, weak cry, and floppiness. Later symptoms include severe speech delay, intellectual disability, seizures, and visual impairment. Over time, muscle…

Van der Woude syndrome is a condition that affects the development of the face. Many people with this disorder are born with a cleft lip and/or a cleft palate. Affected individuals usually have depressions (pits) near the center of the lower lip, which may appear moist due to the presence of salivary and mucous glands in…

Factor XI deficiency is a bleeding disorder that interferes with the body’s clotting process. As a result, people affected by this condition may have difficulty stopping the flow of blood following dental extractions, trauma or surgery. Women with factor XI deficiency may also experience heavy menstrual periods or heavy postpartum bleeding. Within affected people and…

Congenital muscular dystrophy type 1A (MDC1A) belongs to a group of neuromuscular disorders that beings at birth or infancy and is characterized mainly by hypotonia, muscle weakness and muscle wasting. Other signs and symptoms include rigidity of the spine; scoliosis; and delayed, limited motor development, with most individuals needing assistive devices for mobility. Respiratory problems, feeding disorders and seizures may…

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…

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…

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…

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…

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…

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…

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…

empty

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…

Systemic mastocytosis (SM) is a form of mastocytosis in which mast cells accumulate in internal tissues and organs such as the liver, spleen, bone marrow, and small intestines. It is typically diagnosed in adults. Signs and symptoms vary based on which parts of the body are affected. The disorder is usually caused by somatic changes (mutations) in…

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),…

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,…

empty

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…

empty

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%…

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…

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…

empty

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…

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…

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…

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: 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…

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…

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…