Porphyrias are a group of blood conditions caused by a lack of an enzyme in the body that makes heme, an important molecule that carries oxygen throughout the body and is vital for all of the body’s organs. Major types include ALAD deficiency porphyria, acute intermittent porphyria, congenital erythropoietic porphyria, erythropoietic protoporphyria, hepatoerythropoietic porphyria, hereditary coproporphyria, porphyria cutanea tarda, and variegate porphyria….

Anaplastic large cell lymphoma (ALCL) is a rare type of Non-Hodgkins lymphoma. Lymphoma is a cancer of the lymph system, part of our immune system. Non-Hodgkins lymphoma involves abnormal growth of white blood cells, either T cells or B cells. Anaplastic large cell lymphoma is an aggressive cancer that usually involves the T-cells. Cancer cells…

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

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart condition in which the muscle of the right ventricle of the heart is replaced by fat and/or scar tissue. The condition is progressive and over time the right ventricle loses the ability to pump blood.[1] Individuals with ARVC often develop abnormal heart rhythms known as arrhythmias, which can increase…

Usher syndrome type 2A is a genetic condition characterized by hearing loss from birth and progressive vision loss that begins in adolescence or adulthood. Vision loss is due to retinitis pigmentosa. Night vision loss begins first, followed by blind spots that develop in the side (peripheral) vision. Over time, these blind spots enlarge and merge to produce tunnel vision….

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

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

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

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

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

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

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Clouston syndrome is a form of ectodermal dysplasia that is characterized by abnormalities of the skin, hair and nails. Early signs and symptoms generally begin in infancy and may include nail abnormalities and sparse scalp hair that is wiry, brittle, patchy and pale. Progressive hair loss may lead to total alopecia by puberty. Affected people may…

Acute intermittent porphyria (AIP) is one of the liver (hepatic) porphyrias. AIP is caused by low levels of porphobilinogen deaminase (PBGD), an enzyme also often called hydroxymethylbilane synthase. The low levels of PBGD are generally not sufficient to cause symptoms; however, activating factors such as hormones, drugs, and dietary changes may trigger symptoms. Although most individuals with AIP…

Permanent neonatal diabetes mellitus (PNDB) is a type of diabetes that appears within the first 6 months of life and persists throughout life. Affected individuals have slow growth before birth followed by hyperglycemia, dehydration and failure to thrive in infancy. Some individuals also have neurological problems including developmental delay and epilepsy; when these problems are present with…

Primary lateral sclerosis (PLS) is a rare neuromuscular disease that affects the nerve cells that control the voluntary muscles. Problems in the legs (such as weakness, stiffness, spasticity, and balance problems) are often observed first, but hand clumsiness and changes in speech can be early symptoms, as well. The condition is progressive (gradually becomes worse…

Polymyositis is a type of inflammatory myopathy, which refers to a group of muscle diseases characterized by chronic muscle inflammation and weakness. The muscles affected by polymyositis are the skeletal muscles (those involved with making movements) on both sides of the body. Although the disease can affect people of all ages, most cases are seen in adults between…

Oculocutaneous albinism type 1 is a condition that affects the coloring of the skin, hair, and eyes. Signs and symptoms include very fair skin, white hair, an increased risk for skin damage with sun exposure, reduced vision (sharpness), light colored irises, nystagmus, and photophobia (eyes are sensitive to light). It is caused by changes in the TYR…

Complete androgen insensitivity syndrome is a condition that affects sexual development before birth and during puberty. People with this condition are genetically male (one X and one Y chromosome) but do not respond to male hormones at all. As a result, they generally have normal female external genitalia and female breasts. However, they do not…

Townes-Brocks syndrome is a genetic condition characterized by an obstruction of the anal opening (imperforate anus), abnormally shaped ears, and thumb malformations. Most affected individuals have at least two of these three main features. Other signs and symptoms may include kidney abnormalities, hearing loss, heart defects, genital malformations and intellectual disability. The condition is caused by…

Metachromatic leukodystrophy is an inherited condition characterized by the accumulation of fats called sulfatides in cells, especially cells of the nervous system. This accumulation results in progressive destruction of white matter of the brain, which consists of nerve fibers covered by myelin. Affected individuals experience progressive deterioration of intellectual functions and motor skills, such as the…

Mucopolysaccharidosis II (MPS II) is an inherited disorder of carbohydrate metabolism that occurs almost exclusively in males. It is characterized by distinctive facial features, a large head, hydrocephalus, enlargement of the liver and spleen (hepatosplenomegaly), umbilical or inguinal hernia, and hearing loss. Individuals with this condition may additionally have joint deformities and heart abnormalities involving the valves. MPS II…

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Behçet disease is a chronic multisystem inflammatory disorder characterized by ulcers affecting the mouth and genitals, various skin lesions, and abnormalities affecting the eyes. In some people, the disease also results in arthritis (swollen, painful, stiff joints), skin problems, and inflammation of the digestive tract, brain, and spinal cord.[1][2][3] Although it can happen at any age, symptoms generally begin…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 678 Definition Papillon-Lefèvre syndrome (PLS) is a rare ectodermal dysplasia characterized by palmoplantar keratoderma associated with early-onset periodontitis. Epidemiology The prevalence is estimated between 1/250,000 and 1/1,000,000 individuals. The male to female ratio is 1:1….

Intraocular melanoma is a cancer of the pigment-producing cells (melanocytes) in the middle layer of the eye, called the uveal tract.[1] The uveal tract has 3 main parts: (1) the choroid (the tissue layer filled with blood vessels); (2) the ciliary body (the ring of muscle tissue that changes the size of the pupil and the shape of the…

Familial lipoprotein lipase deficiency is a rare genetic disorder is which a person lacks the enzyme lipoprotein lipase, a protein needed to break down fat molecules. Deficiency of this enzyme prevents affected individuals from properly digesting certain fats. This results in the accumulation of fatty droplets called chylomicrons in the blood and an increase in…

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

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

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

Apert syndrome is characterized by fusion of the skull bones too early during development (craniosynostosis) and webbing of fingers and toes (syndactyly). Other signs and symptoms may include distinctive facial features, some of which may lead to dental and vision problems. People with Apert syndrome may also have mild to moderate intellectual disability.[1][2]  Apert syndrome…

Epidermolysis bullosa simplex (EBS) is one of the major forms of epidermolysis bullosa, a group of genetic conditions that cause the skin to be very fragile and to blister easily. EBS is classified into two groups of subtypes by the layer of skin at which the peeling originates. The basal subtypes cause skin peeling at…

Henoch-Schonlein purpura (HSP), also called immunoglobulin A vasculitis (IgAV), is a vascular disease that primarily affects small blood vessels. The disease is characterized by abnormal deposits of immunoglobulin A (an antibody) in the blood vessels, leading to their inflammation (vasculitis). The small vessels of the skin, joints, kidneys, and digestive organs are particularly involved. Signs…

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Congenital primary aphakia (CPA) is a rare eye condition that is present at birth in which the lens is missing. In some cases, CPA can be associated with other eye abnormalities including microphthalmia, absence of the iris, anterior segment aplasia, and/or sclerocornea (when the cornea blends with the sclera). This condition is thought to result from an abnormality during the…

Idiopathic 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…

Glioma refers to a type of brain tumor that develops from the glial cells, which are specialized cells that surround and support neurons (nerve cells) in the brain. It is generally classified based on which type of glial cell is involved in the tumor: Astocytoma tumors that develop from star-shaped glial cells called astrocytes Ependymomas tumors that…

Granulomatosis with polyangiitis (GPA) is a type of vasculitis or swelling (inflammation) of the blood vessels. The disease can cause swelling of the blood vessels anywhere in the body but mainly impacts the sinuses, nose, trachea (windpipe), lungs, and kidneys. The swelling can limit the flow of blood to these body parts, causing damage. Symptoms of…

Hereditary neuropathy with liability to pressure palsies (HNPP) is a disorder that affects peripheral nerves, causing the nerves to be highly sensitive to pressure. Symptoms usually begin during adolescence or early adulthood but may develop anytime from childhood to late adulthood. Symptoms vary in severity. While some people never realize they have the disorder, others experience prolonged disability….

Hypokalemic periodic paralysis (HOKPP) is characterized by episodes of muscle paralysis associated with a fall in blood potassium levels (hypokalemia).[1] Episodes typically involve a temporary inability to move muscles in the arms and legs.[2] The first attack usually occurs in childhood or adolescence. Attacks can last for hours or days, and the frequency of attacks varies among people…

Birdshot chorioretinopathy is an eye condition in which painless, light-colored spots develop on the retina. These spots are scattered in a “birdshot” pattern. The effects of this condition on vision are quite variable; some individuals’ vision is only mildly affected, whereas others experience a significant decline in vision, the appearance of floaters (small specks that appear…

Mantle cell lymphoma (MCL) belongs to a group of diseases known as non-Hodgkin’s lymphomas (NHL). NHL’s are cancers that affect the the lymphatic system (part of the immune system). In MCL, there are cancerous B-cells (a type of immune system cell). The cancerous B-cells are within a region of the lymph node known as the…

Intracranial arteriovenous malformations (AVMs) are abnormal connections between the arteries and veins in the brain.[1] Most people with brain or spinal AVMs experience few, if any, major symptoms. About 12 percent of people with this condition experience symptoms that vary greatly in severity. Seizures and headaches are the most common symptoms of AVMs but individuals…

Mucopolysaccharidosis type IV (MPS IV), also known as Morquio syndrome, is a rare metabolic condition in which the body is unable to break down long chains of sugar molecules called glycosaminoglycans. As a result, toxic levels of these sugars accumulate in cell structures called lysosomes, leading to the various signs and symptoms associated with the…

Netherton disease is a rare disorder affecting the skin, hair and immune system. Symptoms are present at birth and include red, scaly skin. Other symptoms include outbreaks of red, circular scaly rashes, thin, fragile hair (bamboo hair), and immune reactions such as hay fever, asthma, itchy skin, and eczema. Dehydration and infection are common and…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 64747 Definition A disorder that belongs to the genetically heterogeneous group of CMT peripheral sensorimotor polyneuropathy diseases. Clinical description CMTX1 is characterized by a slowly progressive course: muscle wasting and weakness of distal limb muscles…

Hartnup disease is a metabolic disorder characterized by abnormal transport of certain amino acids in the kidney and gastrointestinal system. It is a type of aminoaciduria. The condition may be diagnosed based on the results of newborn screening tests. Most people with the condition have no symptoms (asymptomatic). For those who do show symptoms, the onset of…

Transposition of the great arteries (TGA) is a type of congenital heart defect in which there is a reversal of the normal connections of the aorta and the pulmonary artery with the heart. The aorta and pulmonary artery are reversed, which causes oxygen-poor blood to be circulated to the body and oxygen-rich blood to be circulated between the…

Diffuse large Bcell lymphoma (DLBCL), a form of non-Hodgkin lymphoma, is the most common blood cancer. Lymphomas occur when cells of the immune system, known as B lymphocytes, grow and multiply uncontrollably. DLBCL occurs mostly in adults and is a fast-growing (aggressive) lymphoma. It can start in the lymph nodes or outside of the lymphatic system…

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…

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)….

Atypical hemolytic uremic syndrome (aHUS) is a disease that causes abnormal blood clots to form in small blood vessels in the kidneys. These clots can cause serious medical problems if they restrict or block blood flow, including hemolytic anemia, thrombocytopenia, and kidney failure. It can occur at any age and is often caused by a…

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…

Enthesitis-related juvenile idiopathic arthritis is a subtype of juvenile idiopathic arthritis that is characterized by both arthritis and inflammation of an enthesitis site (the point at which a ligament, tendon, or joint capsule attaches to the bone). Signs and symptoms generally develop in late childhood or early adolescence and include pain, tenderness, and swelling in…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 98957 Definition Gelatinous drop-like corneal dystrophy (GDCD) is a form of superficial corneal dystrophy characterized by multiple prominent milky-white gelatinous nodules beneath the corneal epithelium, and marked visual impairment. Epidemiology Worldwide prevalence of this form…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 3312 Definition Thalidomide embryopathy is a group of anomalies presented in infants as a result of in utero exposure (between 20-36 days after fertilization) to thalidomide, a sedative used in treatment of a range of…

Charcot-Marie-Tooth type 4 (CMT4) is a congenital neurologic hereditary disease, part of a group of peripheral neuropathies known as Charcot-Marie-Tooth disease (CMT). According to the mutated gene CMT4 is classified in CMT4A, CMT4B1, CMT4B2, CMT4B3, CMT4C, CMT4D, CMT4E, CMT4F, CMT4G, CMT4H and CMT4J. Each of these subtypes is very rare and may affect only a particular ethnic…

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…

Limb-girdle muscular dystrophy type 2I (LGMD2I) is a form of limb-girdle muscular dystrophy, which refers to a group of conditions that cause weakness and wasting of the muscles in the arms and legs. The proximal muscles (those closest to the body such as the upper arms and thighs) are generally most affected by the condition.[1]…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 90035 Definition Paroxysmal cold hemoglobinuria (PCH) is a very rare subtype of autoimmune hemolytic anemia (AIHA, see this term), caused by the presence of cold-reacting autoantibodies in the blood and characterized by the sudden presence…

Hereditary pancreatitis causes multiple episodes of inflammation of the pancreas (pancreatitis), an important digestive organ. Symptoms usually begin in childhood and may last a few days or longer. Signs and symptoms may include stomach pain, nausea, or vomiting. People with hereditary pancreatitis develop chronic pancreatitis, a constantly inflamed pancreas. This leads to symptoms which may include…

Opitz G/BBB syndrome is an inherited condition that affects several structures along the midline of the body. The most common features are wide-spaced eyes and defects of the larynx, trachea, and/or esophagus causing breathing problems and difficulty swallowing. Affected males usually have a urethra opening on the underside of the penis (hypospadias). Other features can…

Juvenile Huntington disease (HD) is a less common, early-onset form of Huntington disease that begins in childhood or adolescence. It is a progressive disorder that causes the breakdown of brain cells in certain areas of the brain. This results in uncontrolled movements, loss of intellectual abilities, and emotional disturbances. Juvenile HD is defined by the onset…

Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle inflammation, weakness, and atrophy (wasting). It is a type of inflammatory myopathy. IBM develops in adulthood, usually after age 50. The symptoms and rate of progression vary from person to person. The most common symptoms include progressive weakness of the legs, arms, fingers, and…

CADASIL (Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy) is an inherited disease of the blood vessels that occurs when the thickening of blood vessel walls blocks the flow of blood to the brain. The disease primarily affects the small blood vessels in the white matter of the brain. CADASIL is characterized by migraine headaches and…

Dentinogenesis imperfecta type 2 is a rare and severe form of dentinogenesis imperfecta, a condition that affects tooth development. People affected by the condition may have weak and discolored teeth. These problems can affect both primary (baby) teeth and permanent teeth. People with this form of dentinogenesis imperfecta have no normal teeth. Sensorineural hearing loss…

Primary sclerosing cholangitis (PSC) is characterized by inflammation in the bile ducts (cholangitis) that leads to scarring (sclerosis), narrowing of the ducts, and a buildup of bile in the liver.[1] Early signs and symptoms include extreme tiredness, abdominal pain, and itchiness.[1] As the condition worsens it may cause jaundice, an enlarged spleen, and eventually liver…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 55880 Definition Chondrosarcoma is a malignant bone tumor arising from cartilaginous tissue, most frequently occuring at the ends of the femur and tibia, the proximal end of the humerus and the pelvis; and presenting with…

Shwachman-Diamond syndrome (SDS) affects many parts of the body, particularly the bone marrow, pancreas, and skeletal system. Symptoms include the inability to digest food due to missing digestive enzymes, low muscle tone, and anemia. Other symptoms include skeletal findings and intellectual disability. Children with SDS may have feeding difficulties, slow growth, and frequent infections. People with…

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…

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…

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…

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…