Pigmented villonodular synovitis (PVNS) is a disease in which the tissue lining the joints and tendons in the body (synovium) grows abnormally. It is characterized by a noncancerous mass or tumor. There are two types of PVNS: the local or nodular form (where the tumor involves the tendons that support the joint, or in one area…

Familial adenomatous polyposis (FAP) leads to the growth of hundreds to thousands of non-cancerous (benign) polyps in the colon and rectum. Overtime, the polyps can become cancerous (malignant), leading to colorectal cancer at an average age of 39 years. Symptoms of FAP may include dental abnormalities, tumors of the connective tissue (desmoid tumors), and benign…

Paroxysmal kinesigenic choreoathetosis involves episodes of irregular jerking or shaking movements that are induced by sudden motion, such as standing up quickly or being startled.[1] Cold, hyperventilation, and mental tension have also been reported to trigger attacks in some cases.[2] The exact type of abnormal movement varies among affected individuals but may include prolonged muscle contractions,…

Emery-Dreifuss muscular dystrophy is a condition that affects the joints, muscles, and heart. Joint symptoms tend to present in childhood and involve contractures of the elbows, ankles, and neck. Children and adults with this dystrophy usually experience slowly worsening muscle weakness and wasting. By adulthood, most people with Emery-Dreifuss muscular dystrophy develop heart problems, such as conduction defects and arrhythmias. Emery-Dreifuss muscular dystrophy is caused…

Giant cell arteritis (GCA) is a form of vasculitis, a group of disorders that cause inflammation of blood vessels. GCA most commonly affects the arteries of the head (especially the temporal arteries, located on each side of the head), but arteries in other areas of the body can also become inflamed. The inflammation causes the…

Larsen syndrome is a disorder of the development of the bones. Signs and symptoms may include clubfoot and numerous joint dislocations at birth (affecting the hips, knees and elbows); flexible joints; and a distinctive appearance of the face, hands, feet, and fingers, with square-shape finger tips. The X-rays usually show small extra bones in their…

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Becker muscular dystrophy (BMD) is an inherited condition that causes progressive weakness and wasting of the skeletal and cardiac (heart) muscles. It primarily affects males.[1][2] The age of onset and rate of progression can vary. Muscle weakness usually becomes apparent between the ages of 5 and 15. In some cases, heart involvement (cardiomyopathy) is the…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 93930 Definition A congenital genitourinary malformation belonging to the spectrum of the exstrophy-epispadias complex (EEC) and is characterized by an evaginated bladder plate, epispadias and an anterior defect of the pelvis, pelvic floor and abdominal…

Incontinentia pigmenti (IP) is a genetic condition that affects the skin and other body systems. Skin symptoms change with time and begin with a blistering rash in infancy, followed by wart-like skin growths. The growths become swirled grey or brown patches in childhood, and then swirled light patches in adulthood. Other signs and symptoms may include hair loss, small or missing teeth, eye…

Buerger disease is a disease in which small and medium-sized blood vessels in the arms and/or legs become inflamed and blocked (vasculitis).[1][2] This reduces blood flow to affected areas of the body, eventually resulting damage to tissues.[1] Symptoms of Buerger disease may include coldness, numbness, tingling or burning, and pain. Symptoms may first be felt…

Lymphatic malformations or lymphangiomas are benign (non-cancerous) vascular lesions made of fluid-filled spaces (cysts) thought to occur due to abnormal development of the lymphatic system.[1] In general, lymphatic malformations are categorized into macrocystic, microcystic, or combined depending on the size of the cysts; they are also classified in superficial lesions known as lymphangioma circumscriptum, and more deep-seated lesions…

Mastocytosis occurs when too many mast cells accumulate in the skin and/or internal organs such as the liver, spleen, bone marrow, and small intestines. Mast cells are a type of white blood cell in the immune system. Mast cells are responsible for protecting the body from infection and releasing chemicals to create inflammatory responses.[1] The signs and symptoms of mastocytosis vary based…

Congenital hyperinsulinism is a disease where there are abnormally high levels of insulin, a hormone produced by the beta cells of the pancreas that helps control blood sugar levels. Because of the high levels of insulin, people with this disease have frequent episodes of low blood sugar (hypoglycemia) that can even occur after eating. In…

Mercury poisoning is a condition that occurs in people who are exposed to toxic levels of the element, mercury. There are three different forms of mercury that can cause health problems: Elemental mercury (also known as liquid mercury or quicksilver) can be found in glass thermometers, electrical switches, dental fillings and fluorescent light bulbs. This…

Cone-rod dystrophy (CRD) is a group of inherited eye disorders that affect the light sensitive cells of the retina called the cones and rods. People with this condition experience vision loss over time as the cones and rods deteriorate.[1][2] Initial signs and symptoms that usually occur in childhood may include decreased sharpness of vision (visual acuity)…

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Aniridia is an eye disorder characterized by a complete or partial absence of the colored part of the eye (the iris) and is usually associated with foveal hypoplasia (underdevelopment of the part of the eye responsible for sharp central vision). This combination can lead to decreased visual acuity and involuntary eye movements (nystagmus) in affected infants. People…

Fanconi anemia (FA) affects the way genetic information (DNA) is copied and repaired. FA leads to bone marrow failure, skeletal abnormalities, and an increased risk for cancer. People with FA have a decreased number of red blood cells, white blood cells, and platelets leading to anemia, frequent infections, and excessive bleeding. In addition, people with FA…

Aplasia cutis congenita is a condition in which there is congenital (present from birth) absence of skin, with or without the absence of underlying structures such as bone.[1] It most commonly affects the scalp, but any location of the body can be affected.[2] While most people with aplasia cutis congenita have no other abnormalities, some people…

Charcot-Marie-Tooth disease is a group of disorders that affect the peripheral nerves, the nerves running from outside the brain and spine.[1] Defects in many different genes cause different forms of this disease. Common symptoms may include foot drop, foot deformity, loss of lower leg muscle, numbness in the foot or leg, “slapping” gait (feet hit…

Mucopolysaccharidosis type IIIA (MPS IIIA) is a severe, progressive disorder that affects the central nervous system.[1] In people with MPS IIIA, the body cannot break down a large sugar molecule called heparin sulfate.[2][3] Signs and symptoms usually begin in early childhood and include severe neurological symptoms such as progressive dementia, aggressive behavior, hyperactivity, seizures, deafness,…

Multiple myeloma is a form of cancer that occurs due to abnormal and uncontrolled growth of plasma cells in the bone marrow. Some people with multiple myeloma, especially those with early stages of the condition, have no concerning signs or symptoms. When present, the most common symptom is anemia, which can be associated with fatigue…

Ullrich congenital muscular dystrophy is a condition that mainly affects skeletal muscles (the muscles used for movement). Affected individuals show severe muscle weakness soon after birth, develop stiff joints (contractures) in their knees and elbows, and may have an unusual range of movement (hypermobility) in their wrists and ankles. This condition is caused by mutations…

Stiff person syndrome (SPS) is a rare, progressive syndrome that affects the nervous system, specifically the brain and spinal cord. Symptoms may include extreme muscle stiffness, rigidity and painful spasms in the trunk and limbs, severely impairing mobility. Spasms can generate enough force to fracture bone. People with SPS often have heightened sensitivity to noise,…

Neuropathy ataxia retinitis pigmentosa (NARP) syndrome is characterized by a variety of signs and symptoms that mainly affect the nervous system. Beginning in childhood or early adulthood, most people with NARP experience numbness, tingling, or pain in the arms and legs (sensory neuropathy); muscle weakness; and problems with balance and coordination (ataxia). Affected individuals may also have…

Spinocerebellar ataxia 2 (SCA2) is a progressive disorder that causes symptoms including uncoordinated movement (ataxia), speech and swallowing difficulties, muscle wasting, slow eye movement, and sometimes dementia. Signs and symptoms usually begin in mid-adulthood but can appear any time from childhood to late-adulthood. SCA2 is caused by mutations in the ATXN2 gene and is inherited…

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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…

Hemophilia B is a bleeding disorder that slows the blood clotting process. People with this disorder experience prolonged bleeding or oozing following an injury or surgery. In severe cases of hemophilia, heavy bleeding occurs after minor injury or even in the absence of injury. Serious complications can result from bleeding into the joints, muscles, brain, or other…

Maturity-onset diabetes of the young (MODY) is a form of diabetes that is characterized by an early onset diabetes. MODY represents about 2% of all diabetes cases and is commonly misdiagnosed as type 1 or type 2 diabetes mellitus. It is due to a primary defect in pancreatic β-cell function.[1] There are several MODY subtypes…

FIRES (Febrile Infection-Related Epilepsy Syndrome) is a sub-type of cryptogenic new-onset refractory status epilepticus (NORSE). NORSE describes a condition in which a healthy person who has not had seizures before, begins having seizures. Over a few days, the seizures increase in frequency and length and evolve into status epilepticus (SE). SE is a prolonged seizure or cluster of…

Essential thrombocythemia belongs to a group of diseases called myeloproliferative neoplasms, which cause the bone marrow to make too many platelets, white blood cells and/or red blood cells. In essential thrombocythemia, the body produces too many platelets. The signs and symptoms vary from person to person, but most people with essential thrombocythemia do not have any symptoms when…

Ataxia telangiectasia (A-T) is rare condition that affects the nervous system, the immune system, and many other parts of the body. Signs and symptoms of the condition usually begin in early childhood, often before age 5. The condition is typically characterized by cerebellar ataxia (uncoordinated muscle movements), oculomotor apraxia, telangiectasias, choreoathetosis (uncontrollable movements of the limbs),…

Maple syrup urine disease (MSUD) occurs when the body is unable to breakdown certain parts of proteins. This leads to the build-up of toxic substances that can cause organ and brain damage. There are several forms of MSUD. The most common is the classic or infantile form. Symptoms of the classic form of MSUD start in…

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Isovaleric acidemia (IVA) occurs when the body cannot breakdown certain parts of the proteins found in food. This can cause a build-up of toxic substances which can lead to bouts of serious illness known as metabolic crises. There are two types of IVA. The acute, neonatal type has more severe symptoms that begin in the…

Spinocerebellar ataxia type 1 (SCA1) is a progressive movement disorder that typically begins in early adulthood (but can affect children and older adults as well). Early signs and symptoms includes problems with coordination and balance (ataxia), speech and swallowing difficulties, muscle stiffness, and weakness in the muscles that control eye movement. Over time, SCA1 may…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 54370 Definition Membranoproliferative glomerulonephritis (MPGN) is a chronic progressive kidney disorder characterized by glomerular capillary wall structural changes and mesangial cell proliferation leading to nephrotic syndrome, hypocomplementemia, hypertension, proteinuria and end-stage kidney disease. MPGN can…

Worster-Drought syndrome (WDS) is a condition that affects the muscles of the mouth and throat; it is considered a type of cerebral palsy.[1] The main symptoms of WDS include difficulties with drooling, swallowing and speaking. Some affected individuals may also have challenges with intelligence, behavior, or seizures. The cause of WDS is currently unknown, though it is believed…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 98969 Definition Macular corneal dystrophy (MCD) is a rare, severe form of stromal corneal dystrophy (see this term) characterized by bilateral ill-defined cloudy regions within a hazy stroma, and eventually severe visual impairment. Epidemiology Prevalence…

Angelman syndrome is a genetic disorder that primarily affects the nervous system. Characteristic features of this condition include developmental delay, intellectual disability, severe speech impairment, problems with movement and balance (ataxia), epilepsy, and a small head size. Individuals with Angelman syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. Many…

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47, XYY syndrome is a syndrome (group of signs and symptoms) that affects males. For some males with this syndrome, signs and symptoms are barely noticeable. For others, signs and symptoms may include learning disabilities, speech delay, low muscle tone (hypotonia), and being taller than expected.[1][2] 47, XYY syndrome is caused by having an extra…

Spinal muscular atrophy type 2 (SMA2) is a genetic neuromuscular disorder that affects the nerve cells that control voluntary muscles (motor neurons). Without treatment, progressive muscle weakness develops in babies with SMA2 between ages 6 and 12 months. Babies with SMA2 can sit without support, however, they cannot stand or walk independently. Feeding and breathing problems…

Fragile X syndrome is a genetic condition involving changes in part of the X chromosome.[1] This condition causes a range of developmental problems including learning disabilities and cognitive impairment.[2] It is the most common form of inherited intellectual disability in males and a significant cause of intellectual disability in females.[1] Other signs and symptoms may include…

Pendred syndrome is a condition usually characterized by sensorineural hearing loss in both ears (bilateral) and euthyroid goiter (enlargement of the thyroid gland with normal thyroid gland function). The amount of hearing loss varies among affected people. In many cases, significant hearing loss is present at birth. In other cases, hearing loss does not develop…

Heterotaxy is a condition characterized by internal organs that are not arranged as would be expected in the chest and abdomen. Organs are expected to be in a particular orientation inside of the body, known as situs solitus. Heterotaxy occurs when the organs are not in this typical orientation, but are instead in different positions…

Beckwith-Wiedemann syndrome (BWS) is a growth disorder that can affect several parts of the body. Babies and children are larger than normal usually until age 8, when growth slows down, resulting in an average height in adults. Symptoms may include one side or area of the body growing more than the other side (asymmetric growth…

Cornelia de Lange syndrome (CdLS) is a developmental disorder that affects many parts of the body. The severity of the condition and the associated signs and symptoms can vary widely, but may include distinctive facial characteristics, growth delays, intellectual disability and limb defects. Approximately 60% of people affected by CdLS have a disease-causing variation (mutation)…

Leber hereditary optic neuropathy (LHON) is a condition characterized by vision loss. Vision loss is typically the only symptom of LHON. Some families with additional signs and symptoms have been reported and are said to have “LHON plus“, a condition which includes vision loss, tremors, and abnormalities of the electrical signals that control the heartbeat…

Congenital bilateral absence of the vas deferens (CBAVD) occurs in males when the tubes that carry sperm out of the testes (vas deferens) fail to develop properly. Although the testes usually develop and function normally, sperm cannot be transported through the vas deferens to become part of semen. As a result, men with this condition are…

Meconium aspiration syndrome is a serious condition in which a newborn breathes a mixture of meconium and amniotic fluid into the lungs around the time of delivery. This can cause breathing difficulties due to swelling (inflammation) in the baby’s lungs after birth. Treatment may include suctioning the newborn’s mouth as soon as the head emerges…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1941 Definition Juvenile absence epilepsy (JAE) is a genetic epilepsy with onset occurring around puberty. JAE is characterized by sporadic occurrence of absence seizures, frequently associated with a long-life prevalence of generalized tonic-clonic seizures (GTCS)…

Chromosome 18p deletion is a chromosome abnormality that occurs when there is a missing (deleted) copy of genetic material on the short arm (p) of chromosome 18. The severity of the condition and the signs and symptoms depend on the size and location of the deletion and which genes are involved. Features that often occur…

Mucopolysaccharidosis type III (MPS III) is a 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…

Cleidocranial dysplasia (CCD) affects the development of the bones, skull, and teeth. Signs and symptoms include underdeveloped or absent collarbones (clavicles), dental abnormalities, and delayed closing of the spaces between the skull bones (fontanels). Other symptoms may include decreased bone density (osteopenia), hearing loss, bone abnormalities of the hands, and recurrent sinus and ear infections. People with…

Osteosarcoma is the most common type of bone cancer. The average age at diagnosis is 15. Boys and girls have a similar incidence of this tumor until late adolescence, at which time boys are more commonly affected. In rare cases, osteosarcoma occurs in adults. Although osteosarcoma tends to occur in the larger bones, such as the…

Hereditary coproporphyria (HCP) is a rare inherited form of liver (hepatic) porphyria, characterized by neurological symptoms in the form of episodes (acute attacks) of stomach pain, nausea, vomiting, weakness, numbness, and pain in the hands and feet (neuropathy).[1][2] The porphyrias are a group of blood conditions caused by a lack of an enzyme in the body that…

Tularemia is an infection caused by the bacterium Francisella tularensis. It is more common in rodents and rabbits but has been found in other animals including domestic cats, sheep, birds, and hamsters. Humans can become infected in several different ways: by handling infected animals, through tick or deer fly bites, by drinking contaminated water, or…

Achondroplasia is a disorder of bone growth that prevents the changing of cartilage (particularly in the long bones of the arms and legs) to bone. It is characterized by dwarfism, limited range of motion at the elbows, large head size (macrocephaly), small fingers, and normal intelligence. Achondroplasia can cause health complications such as interruption of…

Syndactyly type 1 is a congenital limb developmental defect that involves webbing or joining of the fingers or toes. Syndactyly type 1 is the most common type of non-syndromic syndactyly. Individuals with syndactyly type 1 have webbing of the third and fourth fingers and/or between the second and third toes. Other digits may be involved, as…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 100984 Definition A rare, pure or complex subtype of hereditary spastic paraplegia, with highly variable phenotype, typically characterized by childhood-onset of minimally progressive, bilateral, mainly symmetric lower limb spasticity and weakness, associated with pes cavus,…

Ollier disease is a skeletal disorder characterized by multiple enchondromas, which are noncancerous (benign) growths of cartilage that develop within the bones. These growths may lead to skeletal deformities, limb discrepancy, and fractures.[1][2][3][4] The enchondromas primarily occur in the limb bones, especially the bones of the hands and feet. They tend to develop near the ends…

Eosinophilic granulomatosis with polyangiitis (Churg Strauss syndrome) is a condition characterized by asthma, high levels of eosinophils (a type of white blood cell that helps fight infection), and inflammation of small to medium sized blood vessels (vasculitis). The inflamed vessels can affect various organ systems including the lungs, gastrointestinal tract, skin, heart and nervous system….

Krabbe disease affects the development and function of the nervous system. There are several types of Krabbe disease that differ based on the age that symptoms begin. The early-onset type of Krabbe disease is the most common and the most severe. Babies who have early-onset (infantile) Krabbe disease typically develop features in the first six months…

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Wilson disease is a rare inherited disorder that is characterized by the accumulation of copper in the body. Because high levels of copper are toxic to tissues and organs, this buildup can lead to damage of the liver, brain and eyes. Signs and symptoms of Wilson disease include chronic liver disease, central nervous system abnormalities, and…

Epidermolytic ichthyosis (EI) is a rare, genetic skin disorder. It becomes apparent at birth, or shortly after birth, with reddening, scaling, and severe blistering of the skin. Hyperkeratosis (thickening of the skin) develops within months and worsens over time. Blister formation decreases, but may still occur after skin trauma or during summer months. Skin can be itchy…

Biotinidase deficiency is an inherited disorder in which the body is unable to recycle the vitamin biotin. The disorder may become apparent in the first few months of life, or later in childhood. The more severe form of the disorder is called ‘profound biotinidase deficiency’ and may cause delayed development, seizures, weak muscle tone (hypotonia),…

Charcot-Marie-Tooth disease type 1A (CMT1A) is a type of inherited neurological disorder that affects the peripheral nerves. People with this disease experience weakness and wasting (atrophy) of the muscles of the lower legs beginning in adolescence; later they can also have hand weakness and sensory loss.[1] In CMT1A, abnormal nerve conduction studies can be found in babies or…

Mixed connective tissue disease (MCTD) is a rare autoimmune disorder that is characterized by features commonly seen in three different connective tissue disorders: systemic lupus erythematosus, scleroderma, and polymyositis. Some affected people may also have symptoms of rheumatoid arthritis.[1] Although MCTD can affect people of all ages, it appears to be most common in women…

Congenital cytomegalovirus (congenital CMV) is a group of symptoms that may occur when an infant is infected with the cytomegalovirus before birth. Most infants who are infected with the virus never develop symptoms of the condition. However, approximately 10% of babies will experience health problems and/or disabilities such as problems with the lungs, liver and/or…

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Reactive arthritis is a type of infectious arthritis that occurs as a “reaction” to an infection elsewhere in the body. This process may occur weeks or even months after the infection has resolved.[1][2] In addition to joint inflammation, reactive arthritis is associated with two other symptoms: redness and inflammation of the eyes (conjunctivitis) and inflammation of the urinary tract…

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat…

Polycythemia vera is a condition characterized by an increased number of red blood cells in the bloodstream (erythrocytosis). Affected people may also have excess white blood cells and platelets. Conditions where the body makes too many of these cells are known as myeloproliferative neoplasms.[1] These extra cells cause the blood to be thicker than normal,…

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare disease characterized by a progressive degeneration of the nervous system (neurodegenerative disorder) and buildup of iron in the brain. PKAN is usually classified into two forms: classic and atypical. Classic PKAN causes symptoms in the first ten years of life. The atypical form of PKAN usually occurs after the age of ten and progresses more…

Currarino triad or syndrome is an autosomal dominant hereditary condition which is characterized by the triad of sacral agenesis abnormalities (abnormally developed lower spine), anorectal malformation (most commonly in the form of anorectal stenosis) and presacral mass consisting of a teratoma, anterior sacral meningocele or both. However only 1 out of 5 cases of Currarino…

Hypermobile Ehlers-Danlos syndrome is an inherited connective tissue disorder that is caused by defects in a protein called collagen. It is generally considered the least severe form of Ehlers-Danlos syndrome (EDS) although significant complications can occur. Common symptoms include joint hypermobility, affecting both large (elbows, knees) and small (fingers, toes) joints; soft, smooth skin that may be…

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Adrenocortical carcinoma is a rare cancer affecting the outside of the adrenal glands (adrenal cortex). These glands are on top of each kidney and are responsible for producing certain hormones and keeping blood pressure at normal levels. Adrenocortical carcinoma is relatively frequent in children compared to many other cancers, although the cancer may also affect…

Gaucher disease refers to a group of inherited metabolic diseases in which harmful amounts of fatty materials (lipids) accumulate in various cells and tissues in the body (lipid storage disorder).[1][2] Signs and symptoms vary widely among affected individuals and may include skeletal disorders, enlarged spleen and liver (hepatosplenomegaly), liver malfunction, anemia, low platelet counts, bone problems,…

Acute myeloid leukemia (AML) is a cancer that affects the blood and bone marrow. Conditions are generally called “acute” when they develop quickly and have an aggressive course. The signs and symptoms of AML vary but may include easy bruising; bone pain or tenderness; fatigue; fever; frequent nosebleeds; bleeding from the gums; shortness of breath;…

Cushing’s syndrome is an endocrine disorder caused by prolonged exposure of the body’s tissues to high levels of cortisol (a hormone produced by the adrenal gland). It most commonly affects adults between age 20 and 50 years. Signs and symptoms of Cushing’s syndrome include upper body obesity, fatigue, muscle weakness, high blood pressure, backache, high…

Free-living amebae belonging to the genera Acanthamoeba, Balamuthia, Naegleria and Sappinia are important causes of disease in humans and animals. Naegleria fowleri produces an acute, and usually lethal, central nervous system (CNS) disease called primary amebic meningoencephalitis (PAM). Acanthamoeba spp. and Balamuthia mandrillaris are opportunistic free-living amebae capable of causing granulomatous amebic encephalitis (GAE) in…

Hereditary spastic paraplegia (HSP) is a group of hereditary, degenerative, neurological disorders that primarily affect the upper motor neurons. Upper motor neurons in the brain and spinal cord deliver signals to the lower motor neurons, which in turn, carry messages to the muscles. In hereditary spastic paraplegia, upper motor neurons slowly degenerate so the muscles do not receive…

Laron syndrome is a condition that occurs when the body is unable to utilize growth hormone. It is primarily characterized by short stature. Other signs and symptoms vary but may include reduced muscle strength and endurance; hypoglycemia in infancy; delayed puberty; short limbs (arms and legs); and obesity. It is often caused by changes (mutations) in…

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a genetic disorder that causes an abnormally fast and irregular heart rhythm in response to physical activity or emotional stress. Signs and symptoms include light-headedness, dizziness, and fainting. Symptoms most often develop between 7 to 9 years of age. If untreated CPVT can cause a heart attack and death. CPVT is caused…

Dentinogenesis imperfecta is a condition characterized by teeth that are translucent and discolored (most often blue-grey or yellow-brown in color). Individuals with this disorder tend to have teeth that are weaker than normal, which leads to wear, breakage, and loss of teeth. This damage can include teeth fractures or small holes (pitting) in the enamel….

Malaria is a serious and sometimes fatal disease caused by a parasite that commonly infects a certain type of mosquito which feeds on humans. Infection with malaria parasites may result in a wide variety of symptoms, ranging from absent or very mild symptoms to severe disease and even death. People who get malaria are typically…

Waardenburg syndrome (WS) is a group of genetic conditions characterized by varying degrees of hearing loss and differences in the coloring (pigmentation) of the eyes, hair, and skin. Signs and symptoms can vary both within and between families. Common features include congenital sensorineural deafness; pale blue eyes, different colored eyes, or two colors within one eye; a…

Miyoshi myopathy is a type of muscular dystrophy characterized by muscle weakness and atrophy (wasting), mainly in the distal parts of the legs.[1] The first symptoms typically begin in young adulthood (on average 20 years of age) and include weakness and atrophy of the calves (sometimes asymmetrically), leading to inability to jump, run or walk on tiptoes. Over…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1209 Definition Tricuspid atresia is (TA) a rare congenital heart malformation characterized by the congenital agenesis of tricuspid valve leading to severe hypoplasia of right ventricle (functionally univentricular). TA is associated with normally related or…

Spinocerebellar ataxia type 6 (SCA6) is a neurological condition characterized by progressive problems with movement. Initial symptoms include problems with coordination and balance (ataxia). Other early signs and symptoms include speech difficulties (dysarthria), involuntary eye movements (nystagmus), and double vision. Over time, individuals with SCA6 may develop loss of coordination in their arms, tremors, and uncontrolled muscle…

Gaucher disease type 1 (GD1) is the most common form of Gaucher disease. Like other types of Gaucher disease, GD1 is caused when not enough glucocerebrosidase (GBA) is made. GBA is an important enzyme that breaks down a fatty chemical called glucocerebroside.[1][2][3] Because the body cannot break down this chemical, fat-filled Gaucher cells build up in…

Hyperkalemic periodic paralysis is a genetic disease that causes episodes of extreme muscle weakness and an increase of the potassium levels in the blood. Muscle weakness during an attack usually affects the arms and legs and muscles of the eyes, throat, and trunk. Most often, these episodes involve a temporary inability to move muscles in…