Dandy-Walker complex is a group of disorders that affect the development of the brain. The changes in brain development are present from birth (congenital). Dandy-Walker complex affects the formation of the area of the brain known as the cerebellum, which is responsible for coordinating movement, and the fluid-filled spaces around it. People with Dandy-Walker complex…

Wolfram syndrome, which is also known by the acronym DIDMOAD, is an inherited condition characterized by diabetes insipidus (DI), childhood-onset diabetes mellitus (DM), a gradual loss of vision caused by optic atrophy (OA), and deafness (D).[1] Other symptoms may include bladder and bowel dysfunction, problems with the parts of the inner ear and brain that…

Parsonage Turner syndrome (PTS) is characterized by the sudden onset of shoulder and upper arm pain followed by progressive (worsening over time) weakness and/or atrophy of the affected area. The pain is felt along the path of one or more nerves and often has no obvious physical cause. The network of nerves involved in this syndrome is called…

Duchenne muscular dystrophy (DMD) affects the muscles, leading to muscle wasting that gets worse over time. DMD occurs primarily in males, though in rare cases may affect females. The symptoms of DMD include progressive weakness and loss (atrophy) of both skeletal and heart muscle. Early signs may include delayed ability to sit, stand, or walk…

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…

Multiple epiphyseal dysplasia (MED) is a group of disorders of cartilage and bone development, primarily affecting the ends of the long bones in the arms and legs (epiphyses). There are two types of MED, which are distinguished by their patterns of inheritance autosomal dominant and autosomal recessive. Signs and symptoms may include joint pain in…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 79434 Definition Oculocutaneous albinism type 1B (OCA1B) is a type of OCA1 (see this term) characterized by skin and hair hypopigmentation, nystagmus, reduced iris and retinal pigment and misrouting of the optic nerves. Epidemiology The…

Aplastic anemia is a blood disorder caused by failure of the bone marrow to make enough new blood cells. Bone marrow is a sponge-like tissue inside the bones that makes stem cells that develop into red blood cells, white blood cells, and platelets.[1] Symptoms may include fatigue, weakness, dizziness, shortness of breath, frequent infections, and bleeding….

Antisynthetase syndrome is a chronic autoimmune condition that affects the muscles and various other parts of the body. The signs and symptoms can vary but may include muscle inflammation (myositis), polyarthritis (inflammation of many joints), interstitial lung disease, thickening and cracking of the hands, and Raynaud phenomenon. The exact underlying cause is unknown; however, the production of…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 3329 Definition Tibial aplasia-ectrodactyly syndrome is a rare condition characterized by congenital ectrodactylous limb malformations associated with tibial aplasia or hypoplasia. Epidemiology The incidence is estimated to be approximately 1 in 1,000,000 live births. Clinical…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 583 Definition Mucopolysaccharidosis type 6 (MPS 6) is a lysosomal storage disease with progressive multisystem involvement, associated with a deficiency of arylsulfatase B (ASB) leading to the accumulation of dermatan sulfate. Epidemiology Birth prevalence is…

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…

Hypereosinophilic syndrome (HES) refers to a rare group of conditions that are associated with persistent eosinophilia with evidence of organ involvement. Signs and symptoms vary significantly based on which parts of the body are affected. Although any organ system can be involved in HES, the heart, central nervous system, skin, and respiratory tract are the…

Multifocal motor neuropathy (MMN) causes damage to the nerves in the arms and legs. Nerve damage begins in adulthood and slowly gets worse over time. One side of the body may be more affected than the other. Symptoms of MMN may include weakness in the hands and lower arms; cramping; involuntary contractions or twitching; wrist…

Coffin-Lowry syndrome is a genetic condition that affects many parts of the body. The signs and symptoms and severity vary from person to person; however, males are typically more severely affected than females. Signs and symptoms may include distinct facial findings, short stature, microcephaly, kyphoscoliosis, other skeletal abnormalities, stimulus-induced drop episodes, intellectual disability and delayed development. Mutations…

Congenital dyserythropoietic anemia is a hereditary disease that affects the production of red blood cells (erythropoiesis) and is characterized by anemia and problems in various organs. The signs and symptoms may include fatigue, weakness, pale skin, yellowing of the skin and eyes (jaundice), larger-than-normal liver and spleen (hepatosplenomegaly), and problems of the heart.[1] There are…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1177 Definition Early onset cerebellar ataxia with retained reflexes (EOCARR) or Harding ataxia is a cerebellar ataxia characterized by the progressive association of a cerebellar and pyramidal syndrome with progressive cerebellar ataxia, brisk tendon reflexes,…

X-linked dominant chondrodysplasia punctata 2 (CDPX2), also known as Conradi-Hünermann-Happle syndrome, is a rare form of skeletal dysplasia characterized by skeletal malformations, skin abnormalities, cataracts and short stature. The specific symptoms and severity of the disorder may vary greatly from one individual to another. CDPX2 is caused by mutations in the emopamil binding protein gene, EBP….

Amyloidosis is a group of diseases in which a protein, called amyloid, builds up in the body’s organs and tissues. Amyloidosis AA is also referred to as Secondary amyloidosis or Inflammatory amyloidosis. This disease is caused by a long-lasting infection or inflammatory disease such as rheumatoid arthritis, familial Mediterranean fever, or osteomyelitis. Infection or inflammation in the body causes an increased amount…

Acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cell).[1] It may develop in children or adults. ALL spreads to the blood fairly quickly, and then may spread to other areas of the body such as the lymph nodes, liver, spleen, central…

Progressive familial intrahepatic cholestasis type 2 (PFIC2) is a rare condition that affects the liver. People with this condition generally develop signs and symptoms during infancy, which may include severe itching, jaundice, failure to thrive, portal hypertension (high blood pressure in the vein that provides blood to the liver) and hepatosplenomegaly (enlarged liver and spleen)….

Recurrent respiratory papillomatosis (RRP) is a rare viral disease where tumors (papillomas) grow in the air passages leading from the nose and mouth into the lungs (respiratory tract). There are two types, a juvenile-onset form and an adult-onset form. The tumors can cause a hoarse voice, chronic cough, and difficulty breathing. They may vary in…

Familial partial lipodystrophy (FPLD) is a group of diseases characterized by an abnormal distribution of fat around the body. Specifically, fat is lost in the arms, legs, and hips, and gained around the face and liver. Symptoms usually develop around puberty and include problems breaking down food and resistance to the hormone that helps control…

Factor V deficiency is an inherited bleeding disorder that prevents blood clots from forming properly.[1] This disorder is caused by mutations in the F5 gene, which leads to a deficiency of a protein called coagulation factor V.[2] The reduced amount of factor V may lead to nosebleeds, easy bruising, and excessive bleeding following surgery or…

Kallmann syndrome (KS) is a condition that causes hypogonadotropic hypogonadism (HH) and an impaired sense of smell. HH affects the production of the hormones needed for sexual development. It is present from birth and is due to deficiency of gonadotropin-releasing hormone (GnRH). KS is often diagnosed at puberty due to lack of sexual development. It…

Primary progressive aphasia (PPA) affects a person’s ability to use language to communicate. This includes difficulty making or understanding speech (aphasia).[1] PPA is a specific type of a more general disease called frontotemporal dementia.[2] PPA can be classified into three distinct types which include:[1] Progressive non-fluent aphasia (PNFA) Semantic dementia (SD) Logopenic progressive aphasia (LPA) PPA…

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)….

Optic atrophy 1, also known as optic atrophy type 1 is a disease that affects the optic nerve. The optic nerve carries signals from the eye to the brain about what is seen. People with optic atrophy type 1 have an optic nerve that has lost some tissue (atrophy). This atrophy causes the optic nerve…

Familial Mediterranean fever is an inherited condition characterized by recurrent episodes of painful inflammation in the abdomen, chest, or joints. These episodes are often accompanied by fever and sometimes a rash or headache. Occasionally inflammation may occur in other parts of the body, such as the heart; the membrane surrounding the brain and spinal cord;…

Idiopathic intracranial hypertension (IIH), formerly known as pseudotumor cerebri, is a condition that affects the brain. Pseudotumor cerebri literally translates to “false brain tumor.” This term was used because symptoms of IIH resemble those of brain tumors depsite no tumor being present. Symptoms of IIH may include severe headache, nausea and vomiting, altered vision, and pulsating…

Brugada syndrome is a heart condition that causes a disruption of the normal rhythm in the heart’s lower chambers (ventricular arrhythmia). Signs and symptoms usually develop in adulthood but the diagnosis may be made at any age.[1] Symptoms and complications often occur during rest or sleep, and may include fainting, seizures, difficulty breathing, or sudden…

Psoriatic juvenile idiopathic arthritis is a subtype of juvenile idiopathic arthritis that is characterized by both arthritis and psoriasis. Other signs and symptoms may include dactylitis (inflammation and swelling of an entire finger or toe); nail pitting or splitting; and eye problems. Although the underlying cause of psoriatic juvenile idiopathic arthritis is currently unknown (idiopathic),…

Smith-Magenis syndrome (SMS) is a developmental disorder that affects many parts of the body. The major features of this condition include mild to moderate intellectual disability, delayed speech and language skills, distinctive facial features, sleep disturbances, and behavioral problems. Most people with SMS have a deletion of genetic material in each cell from a specific region…

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

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

Huntington disease (HD) is an inherited condition that causes progressive degeneration of neurons in the brain. Signs and symptoms usually develop between ages 35 to 44 years and may include uncontrolled movements, loss of intellectual abilities, and various emotional and psychiatric problems. People with HD usually live for about 15 to 20 years after the condition begins….

Frontotemporal dementias (FTDs) are a group of neurodegenerative disorders associated with shrinking of the frontal and temporal anterior lobes of the brain.[1] Symptoms include marked changes in social behavior and personality, and/or problems with language. People with behavior changes may have disinhibition (with socially inappropriate behavior), apathy and loss of empathy, hyperorality (eating excessive amounts of…

Craniopharyngioma is a slow-growing, non-cancerous brain tumor that develops near the pituitary gland (a small endocrine gland at the base of the brain which produces several important hormones) and the hypothalamus (an endocrine organ which controls the release of hormones by the pituitary gland).[1][2][3] This tumor most commonly affects children between 5 and 10 years of age; however,…

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

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

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

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…

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…

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

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

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

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

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

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

Acromegaly is a hormonal disorder that results from the pituitary gland producing too much growth hormone (GH). It is most often diagnosed in middle-aged adults, although symptoms can appear at any age. Signs and symptoms include abnormal growth and swelling of the hands and feet; bone changes that; alter various facial features; arthritis; carpal tunnel syndrome; enlargement of body organs; and…

Nephrogenic diabetes insipidus is a disorder in which a defect in the small tubes (tubules) in the kidneys causes a person to produce a large amount of urine. Nephrogenic diabetes insipidus occurs when the kidney tubules, which allow water to be removed from the body or reabsorbed, do not respond to a chemical in the body called antidiuretic hormone (ADH)…

X-linked agammaglobulinema is a primary immunodeficiency characterized by very low levels of immunoglobulins (proteins made by the immune system to help fight infections). People affected by this condition generally begin developing frequent and recurrent bacterial infections from about 6 months of age. Commonly diagnosed infections include lung infections (pneumonia and bronchitis), middle ear infections, conjunctivitis,…

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…

Oculocutaneous albinism type 2 is a genetic condition that affects the coloring (pigmentation) of the skin, hair, and eyes. Affected individuals typically have very fair skin and white or light-colored hair. Long-term sun exposure greatly increases the risk of skin damage and skin cancers, including an aggressive form of skin cancer called melanoma, in people with…

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…

Limb-girdle muscular dystrophy is a group of disorders which affect the voluntary muscles around the hips and shoulders. The conditions are progressive, leading to a loss of muscle strength and bulk over a number of years. Onset may occur in childhood, adolescence, young adulthood, or even later. Males and females are affected in equal numbers.[1] Most…

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…

Argininosuccinic aciduria is an inherited disorder that causes ammonia to accumulate in the blood. Ammonia, which is formed when proteins are broken down in the body, is toxic if the levels become too high. The nervous system is especially sensitive to the effects of excess ammonia. Argininosuccinic aciduria usually becomes evident in the first few…

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

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

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

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

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

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

Hypohidrotic ectodermal dysplasia (HED) is a genetic skin disease. Common symptoms include sparse scalp and body hair, reduced ability to sweat, and missing teeth. HED is caused by mutations in the EDA, EDAR, or EDARADD genes. It may be inherited in an X-linked recessive, autosomal recessive, or autosomal dominant manner depending on the genetic cause of the condition. The X-linked form is the…

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

Neurofibromatosis type 2 (NF2) is a disorder characterized by the growth of noncancerous tumors of the nervous system. Childhood symptoms include skin growths and eye findings. Almost all people with NF2 develop vestibular schwannomas affecting both ears by age 30. Other tumors of the central nervous system (the brain and spinal cord), skin and eye are also…

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…

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…

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…

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…