Hydrocephalus due to congenital stenosis of aqueduct of sylvius (HSAS) is a form of L1 syndrome, which is an inherited disorder that primarily affects the nervous system. Males with HSAS are typically born with severe hydrocephalus and adducted thumbs (bent towards the palm). Other sign and symptoms of the condition include severe intellectual disability and…

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

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

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…

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…

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…

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…

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…

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…

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…

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,…

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…

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,…

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

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

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

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

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

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…

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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Hemophilia A is an inherited bleeding disorder in which the blood does not clot normally.[1][2][3] People with hemophilia A will bleed more than normal after an injury, surgery, or dental procedure. This disorder can be severe, moderate, or mild. In severe cases, heavy bleeding occurs after minor injury or even when there is no injury…

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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Wiskott Aldrich syndrome (WAS) is a disease with immunological deficiency and reduced ability to form blood clots. Signs and symptoms include easy bruising or bleeding due to a decrease in the number and size of platelets; susceptibility to infections and to immune and inflammatory disorders; and an increased risk for some cancers (such as lymphoma). Also, a skin condition known as eczema is common in people…

Anaplastic thyroid cancer (ATC) accounts for less than 2% of all thyroid cancers and is the most aggressive type of thyroid cancer.[1] Most cases of anaplastic thyroid cancer are diagnosed in the sixth to seventh decade of life. Women are more likely to be affected than men.[1] ATC generally occurs in individuals with a history…

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…

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,…

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…

Erythropoietic protoporphyria (EPP) is a type of porphyria. Porphyrias are caused by an abnormality in the heme production process. Heme is essential in enabling our blood cells to carry oxygen and in breaking down chemical compounds in the liver. Erythropoietic protoporphyria is caused by pathogenic variants (mutations) in the FECH gene which lead to an impaired…

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…

Addison’s disease occurs when the adrenal glands do not produce enough (or any) of the hormones, cortisol and aldosterone. These adrenal gland hormones are necessary for balancing water and energy in the body. Symptoms usually develop slowly over time, and may include fatigue, loss of appetite, abdominal pain, and dark patches of skin. Sometimes symptoms…

Primary myelofibrosis is a condition characterized by the buildup of scar tissue (fibrosis) in the spongy tissue tissue inside the bone (bone marrow), the tissue that contains the stem cells that will produce blood cells. Because of the fibrosis, the bone marrow is unable to make enough normal blood cells. In myelofibrosis, the bone marrow…

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…

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…

Friedreich ataxia is an inherited condition that affects the nervous system and causes movement problems. People with this condition develop impaired muscle coordination (ataxia) that worsens over time. Other features include the gradual loss of strength and sensation in the arms and legs, muscle stiffness (spasticity), and impaired speech. Many individuals have a form of heart…

Ectodermal dysplasias (ED) are a group of more than 180 disorders that affect the outer layer of tissue of the embryo (ectoderm) that helps make up the skin, sweat glands, hair, teeth, and nails. Symptoms of ED can range from mild to severe and may include teeth abnormalities; brittle, sparse or absent hair; abnormal fingernails;…

Congenital adrenal hyperplasia (CAH) refers to a group of genetic conditions that affect the adrenal glands. These glands sit on top of the kidneys and are responsible for releasing various types of hormones that the body needs to function. Affected people lack an enzyme the adrenal glands need to make one or more of these…

Spinal muscular atrophy (SMA) is a group of genetic neuromuscular disorders that affect the nerve cells that control voluntary muscles (motor neurons). The loss of motor neurons causes progressive muscle weakness and loss of movement due to muscle wasting (atrophy). The severity of the symptoms, the age at which symptoms, begin, and genetic cause varies…

Rett syndrome is a progressive, neuro-developmental condition that primarily affects girls. Affected girls appear to have normal psychomotor development during the first 6 to 18 months of life, followed by a developmental “plateau,” and then rapid regression in language and motor skills. Additional signs and symptoms may include repetitive, stereotypic hand movements; fits of screaming…

Focal segmental glomerulosclerosis (FSGS) is a type of kidney disorder. It is characterized by scar tissue that forms in some of the glomeruli in the kidney.[1] FSGS may cause non-specific signs and symptoms, including protein in the urine, elevated levels of creatinine, and swelling.[2][3] In many cases the cause of FSGS can not be determined. Some…

Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by too few platelets in the blood. This is because platelets are being destroyed by the immune system. Symptoms may include bruising, nosebleed or bleeding in the mouth, bleeding into the skin, and abnormally heavy menstruation. With treatment, the chance of remission (a symptom-free period) is…

Lennox-Gastaut syndrome is a form of severe epilepsy that begins in childhood. It is characterized by multiple types of seizures and intellectual disability.[1] This condition can be caused by brain malformations, perinatal asphyxia (lack of oxygen), severe head injury, central nervous system infection and inherited degenerative or metabolic conditions. In about one-third of cases, no…

Autoimmune hemolytic anemia (AIHA) occurs when your immune system makes antibodies that attack your red blood cells. This causes a drop in the number of red blood cells, leading to hemolytic anemia.[1][2][3][4] Symptoms may include unusual weakness and fatigue with tachycardia and breathing difficulties, jaundice, dark urine and/or splenomegaly. AIHA can be primary (idiopathic) or result from…

IgA nephropathy is a kidney disorder that occurs when IgA (immunoglobulin A), a protein that helps the body fight infections, settles in the kidneys. IgA nephropathy can occur at any age, even in childhood. After many years, deposits of IgA may cause the kidneys to leak blood and sometimes protein in the urine. In the early…

Narcolepsy is a chronic brain disorder that involves poor control of sleep-wake cycles. People with narcolepsy have episodes of extreme daytime sleepiness and sudden, irresistible bouts of sleep (called “sleep attacks”) that can occur at any time, and may last from seconds or minutes. Other signs and symptoms may include cataplexy (a sudden loss of…