Porphyria cutanea tarda (PCT) is a form of porphyria that primarily affects the skin. People affected by this condition generally experience “photosensitivity,” which causes painful, blistering lesions to develop on sun-exposed areas of the skin (i.e. the hands and face). Skin in these areas may also be particularly fragile with blistering and/or peeling after minor…

Pure autonomic failure (PAF) is a neurodegenerative disease of the autonomic nervous system, which regulates body processes like blood pressure and breathing rate. PAF usually affects only the peripheral autonomic nervous system, which means it does not usually involve the brain and spinal cord (the central nervous system). Symptoms begin in midlife, although they can begin…

Kabuki syndrome is a rare disorder that affects multiple parts of the body. It is present from birth. Specific symptoms and severity can vary. Features often include a characteristic facial appearance; skeletal abnormalities; short stature; heart defects; and intellectual disability.[1][2] Other signs and symptoms may include seizures, microcephaly, weak muscle tone (hypotonia), eye problems, cleft…

Osteochondritis dissecans is a joint condition that occurs when a piece of cartilage and the thin layer of bone beneath it, separates from the end of the bone. If the piece of cartilage and bone remain close to where they detached, they may not cause any symptoms. However, affected people may experience pain, weakness and/or…

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…

Microscopic polyangiitis (MPA) is a disorder that causes blood vessel inflammation (vasculitis), which can lead to organ damage.[1] The kidneys, lungs, nerves, skin, and joints are the most commonly affected areas of the body. MPA is diagnosed in people of all ages, all ethnicities, and both genders.[2] The cause of this disorder is unknown.

Moyamoya disease is a rare, progressive, blood vessel disease caused by blocked arteries at the base of the brain in an area called the basal ganglia. The name “moyamoya” means “puff of smoke” in Japanese and describes the look of the tangled vessels that form to compensate for the blockage. This condition usually affects children,…

Wolf-Hirschhorn syndrome (WHS) is a genetic disorder that affects many parts of the body. The major features include a characteristic facial appearance, delayed growth and development, intellectual disability, low muscle tone (hypotonia), and seizures. Other features may include skeletal abnormalities, congenital heart defects, hearing loss, urinary tract malformations, and/or structural brain abnormalities. WHS is caused…

Kearns-Sayre syndrome (KSS) is a neuromuscular disorder defined by the triad of onset before age 20 years, pigmentary retinopathy (a “salt-and-pepper” pigmentation in the retina that can affect vision, but often leaves it intact), and progressive external ophthalmoplegia (PEO).[1][2][3] In addition, affected individuals have at least one of the following: cardiac conduction block, cerebrospinal fluid protein concentration…

Miller Fisher syndrome is a rare acquired nerve disease considered to be a variant of Guillain-Barré syndrome.[1] The main features are lack of muscle coordination (ataxia), eye muscle weakness resulting in the inability to move the eyes in several directions (ophthalmoplegia), and the absence of tendon reflexes. Symptoms often start several days after a viral…

Dyskeratosis congenita affects many parts of the body. Three features are especially characteristic of this disorder: (1) fingernails and toenails that grow poorly or are abnormally shaped; (2) changes in skin coloring (pigmentation), especially on the neck and chest, that resembles the appearance of lace; and (3) white patches inside the mouth (oral leukoplakia). People with dyskeratosis congenita also have…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 926 Definition A rare congenital disorder resulting from a deficiency in erythrocyte catalase, an enzyme responsible for the breakdown of hydrogen peroxide. Epidemiology The disorder is very rare in the general population with an estimated…

Spinocerebellar ataxia 7 (SCA7) is an inherited disease of the central nervous system that leads to impairment of specific nerve fibers carrying messages to and from the brain, resulting in degeneration of the cerebellum (the coordination center of the brain). SCA7 differs from most other forms of SCA in that visual problems, rather than poor…

Dominant optic atrophy (DOA) is an inherited optic nerve disorder characterized by degeneration of the optic nerves.[1][2] It typically starts during the first decade of life. Affected people usually develop moderate visual loss and color vision defects. The severity varies and visual acuity can range from normal to legal blindness. About 20% of people with…

Hirschsprung disease (HSCR) is a disease of the large intestine or colon. People with this disease do not have the nerve cells in the intestine required to pass stools from the body normally. Symptoms of Hirschsprung disease usually start in very young children, but may occur later. The symptoms may vary with age, but often involve…

Glutaric acidemia type II (GA2) is a disorder that interferes with the body’s ability to break down proteins and fats to produce energy. The severity of GA2 varies widely among affected individuals. Some have a very severe form which appears in the neonatal period and may be fatal; individuals with this form may be born…

Unverricht-Lundborg disease (ULD) is an inherited form of progressive myoclonus epilepsy, a neurodegenerative disorder. Signs and symptoms typically begin during childhood or adolescence and worsen over time. Early symptoms include involuntary muscle jerking or twitching (stimulus-sensitive myoclonus) and tonic-clonic seizures. Episodes of myoclonus may be brought on by exercise, stress, light, or other stimuli (triggers). Over…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1199 Definition Oesophageal atresia (OA) encompasses a group of congenital anomalies with an interruption in the continuity of the oesophagus, with or without persistent communication with the trachea. Epidemiology OA occurs in 1 in 2500…

Progressive pseudorheumatoid disyplasia (PPD) is a disorder of bone and cartilage that affects many joints. It manifests between the age of 3 and 6 years with joint pain and progressive joint stiffness. Major signs and symptoms include stiff joints (contractures), short stature, and widening of the ends of the finger and toe bones as well as other tubular…

Evans syndrome is a very rare autoimmune disorder in which the immune system destroys the body’s red blood cells, white blood cells and/or platelets. Affected people often experience thrombocytopenia (too few platelets) and Coombs’ positive hemolytic anemia (premature destruction of red blood cells). Signs and symptoms may include purpura, paleness, fatigue, and light-headedness. The exact…

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

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 99013 Definition A form of hereditary spastic paraplegia characterized by an onset usually in adulthood (but ranging from 10-72 years) of progressive bilateral lower limb weakness and spasticity, sphincter dysfunction, decreased vibratory sense at the…

A giant congenital nevus is a dark-colored, often hairy patch of skin that is present at birth (congenital). It grows proportionally to the child. A congenital pigmented nevus is considered giant if by adulthood it is larger than 20cm (about 8 inches) in diameter.[1][2] Giant congenital nevi can occur in people of any racial or ethnic background and…

Birt-Hogg-Dube syndrome (BHDS) is a rare, complex, genetic disorder with three main clinical findings: non-cancerous (benign) skin tumors; lung cysts and/or history of pneumothorax (collapsed lung); and various types of renal tumors. Fibrofolliculomas are a type of benign skin tumor specific to BHDS. They typically occur on the face, neck, and upper torso. Most people with BHDS also have multiple cysts in…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 87503 Definition Mal de Meleda (MdM) is a diffuse palmoplantar keratoderma, initially reported in the Island of Meleda, characterized by symmetric palmoplantar hyperkeratosis that progressively extends to the dorsal surfaces of hands and feet (transgrediens)….

Cat eye syndrome is a chromosome abnormality that affects many different parts of the body. The signs and symptoms of the condition vary widely but may include abnormalities of the eyes, ears, anal region, heart and/or kidney.[1][2] In people affected by cat eye syndrome, each cell has at least one small extra (duplicate) chromosome made up…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 85414 Definition Systemic-onset juvenile idiopathic arthritis is marked by the severity of the extra-articular manifestations (fever, cutaneous eruptions) and by an equal sex ratio. Epidemiology It represents 10-11% of cases of juvenile idiopathic arthritis (JIA)….

Weill-Marchesani syndrome is an inherited connective tissue disorder that mainly affects the bones and eyes. People with this syndrome are usually short in height and often have short fingers and limited joint movement, especially of the hands. Weill-Marchesani syndrome also causes problems with the lens of the eye that lead to severe nearsightedness, and it can…

Nonbullous congenital ichthyosiform erythroderma (NBCIE) is a specific type of ichthyosis mainly affecting the skin. Most infants with NBCIE are born with a tight, shiny covering on their skin, called a collodion membrane, which is typically shed within a few weeks. Other signs and symptoms include redness of the skin (erythroderma); fine, white scales on the skin; and thickening of the…

OEIS complex, also known as cloacal exstrophy, is the most severe birth defect within the exstrophy-epispadias complex. It is characterized by Omphalocele, Exstrophy, Imperforate anus and Spinal defects.[1][2] A child with this condition will have the bladder and a portion of the intestines exposed outside the abdomen with the bony pelvis open like a book. In males, the…

Ornithine transcarbamylase (OTC) deficiency is a genetic disease that causes too much ammonia to accumulate in the blood (hyperammonemia). Ammonia is toxic when levels are too high and especially affects the nervous system. Severe OTC deficiency (the early-onset form) typically affects males (and rarely females) and causes symptoms in the newborn period or early childhood….

Dentatorubral-pallidoluysian atrophy (DRPLA) is a brain disorder that worsens over time. It can lead to involuntary movements, mental and emotional problems, and a decline in thinking ability. Symptoms usually appear around 30 years of age, but can occur anytime from infancy to mid-adulthood. Specific signs and symptoms may differ and include seizures, issues with balance…

Blue cone monochromatism is an inherited vision disorder. In this condition, the light sensitive cells in the eye used for color vision (cones) are affected. There are three types of cones that respond to one of three colors: red, green, and blue. When people have blue cone monochromatism, both the red and green cones do…

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…

Von Hippel-Lindau (VHL) disease is an inherited disorder characterized by the abnormal growth of both benign and cancerous tumors and cysts in many parts of the body. Tumors usually first appear in young adulthood. The types of tumors associated with VHL disease include hemangioblastomas (slow-growing tumors of the central nervous system); kidney cysts and clear…

Neurocutaneous melanosis (NCM) is a rare, noninherited condition of the central nervous system. It is characterized by melanocytic nevi in both the skin and the brain.[1][2] Two-thirds of people with NCM have giant congenital melanocytic nevi, and the remaining one-third have numerous lesions but no giant lesions.[1] The typical cutaneous lesions are present at birth….

46,XX testicular disorder of sex development is a condition in which a person with two X chromosomes (which is normally found in females) has a male appearance. More specifically, people with this condition have male external genitalia, ranging from normal to ambiguous. Other common signs and symptoms include small testes, gynecomastia, infertility due to azoospermia…

Chronic hiccups are repeated, unintentional contractions of the breathing muscles that continue for a long period of time. Regular hiccups often develop after eating a large meal or drinking a carbonated beverage, and they typically go away on their own after a couple minutes. Chronic hiccups last over two days and in rare cases, may…

Polyarteritis nodosa (PAN) is a blood vessel disease characterized by inflammation of small and medium-sized arteries (vasculitis), preventing them from bringing oxygen and food to organs.[1][2] Most cases occur in the 4th or 5th decade of life, although it can occur at any age.[3] PAN most commonly affects vessels related to the skin, joints, peripheral nerves,…

Isolated growth hormone deficiency is a condition caused by a severe shortage or absence of growth hormone without other hormonal problems. Growth hormone is a protein necessary for normal growth of the bone and body tissues. Because people with this condition don’t have enough of this hormone, they have short stature, which is noticeable from…

Factor VII deficiency is a rare bleeding disorder. The age of onset and severity varies from person to person. While severe cases may become apparent in infancy, very mild cases may never cause any bleeding problems. Signs and symptoms may include nosebleeds; easy bruising; bleeding gums; excessive or prolonged bleeding after injury or surgery; and…

Acute interstitial pneumonia (AIP) is a rare and serious condition that affects the lungs. The signs and symptoms generally develop and progress rapidly. In the early stages of the condition, affected people may experience upper respiratory and/or viral-like symptoms such as cough, shortness of breath, and fever. This is followed by the rapid onset of…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 212 Definition Cystathioninuria is an autosomal recessive disorder caused by cystathionine gamma-lyase deficiency. It is usually pyridoxine-dependent, but in very rare cases it may be non-dependent. It is generally considered to be a benign condition…

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,…

Variegate porphyria (VP) is an inherited disorder that is caused by mutations in the PPOX gene that lead to the build-up of compounds normally involved in the body’s production of heme.[1][2] Heme is an important part of hemoglobin, the protein in blood that carries oxygen throughout our bodies. It is used in all the body’s…

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…

Russell-Silver syndrome (RSS) is a rare condition associated with poor growth both before and after birth.[1] Signs and symptoms vary and may include low birth weight, short stature, characteristic facial features, large head in relation to body size, body asymmetry, and feeding difficulties. Other features may include poor appetite, clinodactyly (curved finger), digestive system abnormalities, delayed…

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…

Short bowel syndrome is a disorder characterized by malabsorption of nutrients due to problems involving the small intestine.[1] The small intestine is the tube-shaped organ between the stomach and large intestine, which includes the duodenum, jejunum, and ileum, where most food digestion and nutrient absorption take place. The causes of short bowel syndrome in adults…

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)…

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…

47 XXX syndrome, also called trisomy X or triple X syndrome, is characterized by the presence of an additional (third) X chromosome in each of a female’s cells (which normally have two X chromosomes). An extra copy of the X chromosome is associated with tall stature, learning problems, and other features in some girls and women. Seizures or…

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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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…

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)…

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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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…