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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Sarcosinemia is a rare inborn error of metabolism characterized by an increased level of the amino acid sarcosine in the blood and urine.[1] It is reportedly most likely benign, unrelated to significant signs or symptoms.[2][3][4] A number of children have been detected by newborn screening and have remained symptom-free.[5] Some reports have associated sarcosinemia with various symptoms…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 42062 Definition Iminoglycinuria is a metabolic disorder resulting from defective renal tube reabsorption of proline, hydroxyproline and glycine. The prevalence is estimated at around 1 in 15 000. The disorder is usually asymptomatic and is…

Lymphangioleiomyomatosis (lim-FAN-je-o-LI-o-MI-o-ma-TO-sis), or LAM, is a rare cystic lung disease that mostly affects women in their mid-forties. In LAM, an unusual type of cell begins to grow out of control throughout the body, including in the lungs, lymph nodes and vessels, and kidneys. Over time, these LAM cells form cysts and clusters of cells, which…

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Cowden syndrome is an inherited condition that is characterized primarily by multiple, noncancerous growths (called hamartomas) on various parts of the body. People with the syndrome usually have large head (macrocephaly), benign tumors of the hair follicle (trichilemmomas), and white papules with a smooth surface in the mouth (papillomatous papules), starting by the late 20s. It is considered part…

Trisomy 18 is a chromosome disorder characterized by having 3 copies of chromosome 18 instead of the usual 2 copies. Signs and symptoms include severe intellectual disability; low birth weight; a small, abnormally shaped head; a small jaw and mouth; clenched fists with overlapping fingers; congenital heart defects; and various abnormalities of other organs. Trisomy…

Spinal muscular atrophy 1 (SMA1), also known as Werdnig Hoffmann disease, is a genetic neuromuscular disorder that affects the nerve cells that control voluntary muscles (motor neurons). Without treatment, symptoms of SMA1 become apparent before 6 months of age and include worsening muscle weakness and poor muscle tone (hypotonia) due to loss of the lower…

Creutzfeldt-Jakob disease (CJD) is a rare fatal brain disorder that usually occurs later in life and runs a rapid course. In the early stages of the disease, patients may have failing memory, behavior changes, impaired coordination, and vision problems. As CJD progresses, mental deterioration becomes severe, and they can have uncontrolled movements, blindness, weakness, and go into…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 100070 Definition Progressive non-fluent aphasia (PNFA) is a form of frontotemporal dementia (FTD; see this term), characterized by agrammatism, laborious speech, alexia, and agraphia, frequently accompanied by apraxia of speech (AOS). Language comprehension is relatively…

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,…

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: 404 Definition Familial hyperaldosteronism type II (FH-II) is a heritable form of primary aldosteronism (PA) characterized by hypertension of varying severity, and non glucocticoid remediable hyperaldosteronism. Epidemiology PA is the most common form of secondary…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 2019 Definition Femur-fibula-ulna (FFU) complex is a non-lethal congenital anomaly of unknown etiology, more frequently reported in males than females, characterized by a highly variable combination of defects of the femur, fibula, and/or ulna, with…

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…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 30391 Definition Biliary atresia is a rare, progressive obliterative cholangiopathy of the extrahepatic bile ducts, occuring in the embryonic/ perinatal period, leading to severe and persistent jaundice and acholic stool with an unfavorable course in…

Caudal regression sequence (CRS) affects the development of the lower (caudal) half of the body. It can impact the development of the lower back, spinal cord, and lower limbs. The kidneys, bladder, digestive tract, and genitalia may also be affected. CRS occurs during fetal development and is present at birth. The features and severity vary from…

Lowe oculocerebrorenal syndrome is a rare condition that primarily affects the eyes, central nervous system and kidneys. Some of the signs and symptoms associated with the condition are often present from birth, including congenital cataracts and other eye abnormalities; hypotonia (reduced muscle tone); and feeding difficulties. Affected people may also experience kidney problems (such as…

Cystic fibrosis (CF) is a genetic disorder that causes mucus to build up and damage organs in the body, particularly the lungs and pancreas. Signs and symptoms may include salty-tasting skin; persistent coughing; frequent lung infections; wheezing or shortness of breath; poor growth; weight loss; greasy, bulky stools; difficulty with bowel movements; and in males, infertility. Over time,…

Multiple endocrine neoplasia type 2 (MEN2) is an inherited disorder in which one or more of the endocrine glands are overactive or form a tumor. Endocrine glands most commonly involved include:[1] Adrenal (about half the time) Parathyroid (20% of the time) Thyroid (almost all of the time) MEN2 is caused by a defect in the RET gene.[1][2] This defect…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 289560 Definition A rare neurodegenerative disorder characterized by iron accumulation in specific regions of the brain, usually the basal ganglia, and associated with slowly progressive pyramidal (spasticity) and extrapyramidal (dystonia) signs, motor axonal neuropathy, optic…

Multiple system atrophy (MSA) causes the progressive loss of nerve cells in the brain (a neurodegenerative disease). MSA affects several areas of the brain, including the cerebellum, which is involved in controlling movement and some emotions, as well as certain types of learning and memory, and the autonomic nervous system, which controls your body’s automatic, or…

Neurofibromatosis type 1 (NF1) is a genetic condition that affects the skin, the skeleton and the part of the nervous system outside the brain and spinal cord peripheral nervous system). The main signs and symptoms of NF1 include dark colored spots on the skin (café-au-lait spots), benign growths along the nerves (neurofibromas), and freckles in…

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…

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,…

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Leishmaniasis is a parasitic disease spread by the bite of infected sand flies. There are several different forms of leishmaniasis. The most common are cutaneous and visceral. The cutaneous type causes skin sores. The visceral type affects internal organs such as the spleen, liver and bone marrow. People with this form usually have fever, weight…

Diastrophic dysplasia is a disorder of cartilage and bone development.[1] Diastrophic dysplasia is characterized by shortened arms and legs, spinal deformities, hitchhiker thumbs, joint contractures, and joint pain (osteoarthritis).[2] Joint contractures and spinal deformity tend to worsen with age.[2] Mental development and intelligence are usually normal.[2] Occasionally, children with diastrophic dysplasia die in infancy due…

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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…

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…

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…

Familial or sporadic hemiplegic migraine refers to a rare type of migraine with aura that occurs with motor weakness during the aura. The two types of hemiplegic migraine (HM) are distinguished based on the family history: familial hemiplegic migraine (FHM, in which at least one other family member has the condition) and sporadic hemiplegic migraine (SHM, in which there is no…

Ataxia with vitamin E deficiency (AVED) is a progressive disease affecting motor control and movement. Symptoms of AVED include slurred speech (dysarthria), difficulty coordinating movements (ataxia), numbness in the hands and feet (peripheral neuropathy), and progressive leg weakness. Some affected individuals may experience vision loss due to damage to the back of the eye (retinitis…

Kaposi sarcoma (KS) is a cancer that develops from the cells that line lymph or blood vessels. It usually appears as tumors on the skin or on mucosal surfaces such as inside the mouth, but tumors can also develop in other parts of the body (including the lymph nodes, lungs, or digestive tract). The abnormal…

Calciphylaxis is a disease in which blood vessels (veins and arteries) become blocked by a build-up of calcium in the walls of the vessels, preventing blood from flowing to the skin or internal organs. The lack of blood flow (ischemia) damages healthy tissue and causes it to die (necrosis). The most obvious and frequent symptom of…

Central diabetes insipidus (DI) is a form of DI that occurs when the body has lower than normal levels of antidiuretic hormone (vasopressin), which is characterized by frequent urination.[1][2] Diabetes insipidus is subdivided into central and nephrogenic DI. Two other forms are gestational DI and primary polydipsia (dipsogenic DI). Central DI results from damage to the…

Trisomy 13 is a type of chromosome disorder characterized by having 3 copies of chromosome 13 in cells of the body, instead of the usual 2 copies. In some people, only a portion of cells contains the extra chromosome 13 (called mosaic trisomy 13), whereas other cells contain the normal chromosome pair.[1][2][3] Trisomy 13 causes…

Classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (classic 21-OHD CAH) affects the adrenal glands which are responsible for producing specific hormones. There are two types of classic 21-OHD CAH, the salt-wasting form and the simple-virilizing form. Symptoms include abnormal development of the external sex organs in females (ambiguous genitalia), early puberty, and short stature. The…

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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…

Medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD) is an inherited metabolic disorder that prevents the body from converting certain fats to energy, particularly during periods without food (fasting). People with MCADD do not have enough of an enzyme needed to metabolize a group of fats called medium-chain fatty acids. Signs and symptoms usually begin by early…

Vernal keratoconjunctivitis (VKC) is a chronic, severe allergy that affects the surfaces of the eyes. It most commonly occurs in boys living in warm, dry climates. Attacks associated with VKC are common in the spring (hence the name “vernal”) and summer but often reoccur in the winter.[1][2] Signs and symptoms usually begin before 10 years of age and…

Inclusion body myopathy 2, also known as hereditary inclusion body myopathy (HIBM), GNE-related myopathy, distal myopathy with rimmed vacuoles, and Nonaka myopathy, is an inherited condition that primarily affects the skeletal muscles (the muscles that the body uses to move). This disorder is characterized by muscle weakness that appears in late adolescence or early adulthood and worsens over time.[1] Early…

Dopa-responsive dystonia (DRD) is an inherited type of dystonia that typically begins during childhood but may begin in adolescence or adulthood.[1] Depending on the specific type of DRD, specific symptoms can vary. Features can range from mild to severe. In most cases, dystonia begins in the lower limbs and spreads to the upper limbs over…

AL amyloidosisis the most common form of amyloidosis, a group of disorders in which an abnormal protein called amyloid builds up in tissues and organs. The signs and symptoms of AL amyloidosis vary among patients because the build up may occur in the tongue, intestines, muscles, joints, nerves, skin, ligaments, heart, liver, spleen, or kidneys. To diagnose AL…

Alström syndrome is a rare genetic disorder that affects many body systems.[1][2] Symptoms develop gradually, beginning in infancy, and can be variable. In childhood, the disorder is generally characterized by vision and hearing abnormalities, childhood obesity, and heart disease (cardiomyopathy). Over time, diabetes mellitus, liver problems, and slowly progressive kidney dysfunction which can lead to kidney…

Phenylketonuria (PKU) is a genetic metabolic disorder that increases the body’s levels of phenylalanine. Phenylalanine is one of the building blocks (amino acids) of proteins. Humans cannot make phenyalanine, but it is a natural part of the foods we eat. However, people do not need all the phenyalanine they eat, so the body converts extra…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 93476 Definition Hurler-Scheie syndrome is the intermediate form of mucopolysaccharidosis type 1 (MPS1; see this term) between the two extremes Hurler syndrome and Scheie syndrome (see these terms); it is a rare lysosomal storage disease,…

Turner syndrome is a chromosomal disorder that affects development in females. It results when a female’s cells have one normal X chromosome and the other sex chromosome is either missing or structurally altered (females without Turner syndrome have two normal X chromosomes in each cell, and males have one X and one Y chromosome). Signs and symptoms…

Juvenile retinoschisis is an eye condition characterized by impaired vision that begins in childhood and occurs almost exclusively in males. The condition affects the retina, which is a specialized light-sensitive tissue that lines the back of the eye. This affects the sharpness of vision. Central vision is more commonly affected. Vision often deteriorates early in…

Lysosomal acid lipase deficiency is a metabolic lipid storage disease.[1][2] Two rare conditions may result from this deficiency (likely representing two ends of a clinical spectrum):[1][3] Wolman disease: The early-onset and most severe form of the disease where lipids accumulate throughout the body, mostly in the liver, within the first weeks of life. Symptoms include…

Jervell Lange-Nielsen syndrome (JLNS) is an inherited disorder characterized by deafness present at birth and abnormalities of the electrical system of the heart. It is a form of long QT syndrome. This refers to the QT interval measurement seen on the electrocardiogram. The severity of cardiac symptoms seen in individuals varies from no apparent symptoms to increasing…

Joubert syndrome is disorder of brain development that may affect many parts of the body. It is characterized by the absence or underdevelopment of the cerebellar vermis (a part of the brain that controls balance and coordination) and a malformed brain stem (connection between the brain and spinal cord). Together, these cause the characteristic appearance of…

Choroideremia is a genetic condition that causes vision loss. This disorder typically affects males. The first symptom is usually impairment of night vision (night blindness), which can occur in childhood. People with this disorder also experience narrowing of the field of vision (tunnel vision) and decrease in the ability to see details (visual acuity). The…

Ocular albinism type 1 (OA1) is a genetic eye condition that primarily affects males. Signs and symptoms may include reduced coloring of the iris and retina (ocular hypopigmentation); foveal hypoplasia (underdevelopment); rapid, involuntary eye movements (nystagmus); poor vision; poor depth perception; eyes that do not look in the same direction (strabismus); and increased sensitivity to…

Nontuberculous mycobacterial (NTM) lung disease is an infectious condition caused by certain types of mycobacteria. Some people with NTM lung disease have no signs or symptoms, while others experience a severe cough, hemoptysis (coughing up blood), shortness of breath, fatigue, fever, night sweats and/or weightloss. Mycobacteria are found naturally in soil and water. Most people…

X-linked severe combined immunodeficiency (X-SCID) is a severe, genetic condition of the immune system.[1] Signs and symptoms often become apparent in early infancy and include failure to thrive; oral/diaper candidiasis (yeast infection); absent tonsils and lymph nodes; recurrent, persistent infections; rashes; diarrhea; fevers; and pneumonia. X-SCID is caused by mutations in the IL2RG gene and is inherited…

Achalasia is a disorder of the esophagus, the tube that carries food from the mouth to the stomach. It is characterized by enlargement of the esophagus, impaired ability of the esophagus to push food down toward the stomach (peristalsis), and failure of the ring-shaped muscle at the bottom of the esophagus (the lower esophageal sphincter) to relax.[1] Achalasia is…

ACTH-secreting pituitary adenoma is a condition characterized by elevated levels of a hormone called cortisol secreted by a tumor in the pituitary gland. It is part of a group of diseases that cause Cushing’s syndrome, characterized by signs and symptoms that may include weight gain around the trunk and in the face, stretch marks, easy bruising, a hump on…

Myotonic dystrophy is a disease that affects the muscles and other body systems. It is the most common form of muscular dystrophy that begins in adulthood, usually in a person’s 20s or 30s. This disease is characterized by progressive muscle loss and weakness. Myotonic dystrophy may be further classified into two types, and the two…

Ebstein’s anomaly is a rare heart defect in which parts of the tricuspid valve (which separates the right ventricle from the right atrium) are abnormal. The abnormality causes the tricuspid valve to leak blood backwards into the right atrium. The backup of blood flow can lead to heart swelling and fluid buildup in the lungs…

Amyotrophic lateral sclerosis (ALS), also referred to as “Lou Gehrig’s disease,” is a progressive motor neuron disease which leads to problems with muscle control and movement.[1][2] There are various types of ALS that are distinguished by symptoms and, in some cases, genetic cause.[2] Early symptoms may include muscle twitching, cramping, stiffness, or weakness, slurred speech,…

Noonan syndrome is a genetic disorder that causes abnormal development of multiple parts of the body. Features of Noonan syndrome may include a distinctive facial appearance, short stature, a broad or webbed neck, congenital heart defects, bleeding problems, problems with bone structure (skeletal malformations), and developmental delay.[1][2] Noonan syndrome may be caused by a mutation…

Nevoid basal cell carcinoma syndrome (NBCCS) leads to the growth of non-cancerous and cancerous tumors. The symptoms include basal cell cancers, jaw cysts, skin pits on the hands and feet, and abnormal deposits of calcium in the brain. Other symptoms may include bone abnormalities of the spine, ribs, or skull, and a large head. Some of…

X-linked hypophosphatemia (XLH) is an inherited disorder characterized by low levels of phosphate in the blood. Phosphate levels are low because phosphate is abnormally processed in the kidneys, which causes a loss of phosphate in the urine (phosphate wasting) and leads to soft, weak bones (rickets). XLH is usually diagnosed in childhood. Features include bowed…