Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Aicardi syndrome is an extremely rare genetic disorder. Almost all people with Aicardi syndrome are females. Individuals with Aicardi syndrome have agenesis of the corpus callosum, chorioretinal lacunae and seizures. Agenesis of the corpus callosu...

A heart arrhythmia (uh-RITH-me-uh) is an irregular heartbeat. Heart rhythm probl...

A heart arrhythmia (uh-RITH-me-uh) is an irregular heartbeat. Heart rhythm problems (heart arrhythmias) occur when the electrical signals that coordinate the heart's beats don't work properly. The faulty signalling causes the heart to beat too fas...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (a...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other he...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Cyclic vomiting syndrome (CVS) is a rare disorder characterized by recurrent, similar episodes of severe nausea and vomiting. An episode may last for a few hours to several days and then is followed by a period of time during which affected indivi...

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Collagenous colitis is a rare digestive disorder that primarily affects females and typically becomes apparent during middle age. The disorder is characterized by inflammatory changes of the mucous membranes (mucosa) of the colon (colitis) and abn...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Microvillus inclusion disease is an extremely rare inherited intestinal disorder (enteropathy) that is typically apparent within hours or days after birth. The disorder is characterized by chronic, severe, watery diarrhea and insufficient absorpti...

Duodenal atresia or stenosis is a rare congenital digestive disorder that usually occurs for no apparent reason (sporadically). However, a few cases of duodenal atresia have been inherited as an autosomal recessive genetic trait. Duode...

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, ...

Emery-Dreifuss muscular dystrophy (EDMD) is a rare, often slowly progressive genetic disorder affecting the muscles of the arms, legs, face, neck, spine and heart. The disorder consists of the clinical triad of weakness and degeneration (atrophy) ...

Encephalitis (en-sef-uh-LIE-tis) is inflammation of the brain. There are several causes, including viral infection, autoimmune inflammation, bacterial infection, insect bites and others. Sometimes there is no known cause. Encephalitis may ...

Encephaloceles are rare birth defects associated with skull defects characterized by partial lacking of bone fusion leaving a gap through which a portion of the brain sticks out (protrudes). In some cases, cerebrospinal fluid or the membranes that...

Carcinoid syndrome is a disease consisting of a combination of symptoms, physical manifestations, and abnormal laboratory findings. Carcinoid syndrome is seen in individuals who have an underlying carcinoid tumour with spread to the liver. Carcino...

Fibrocystic breast changes  Fibrocystic breast changes lead to the development of fluid-filled round or oval sacs (cysts) and more prominent scar-like (fibrous) tissue, which can make breasts feel tender, lumpy or ropy. Fibroc...

Fountain syndrome is an extremely rare inherited disorder that is characterized by mental retardation; abnormal swelling of the cheeks and lips due to the excessive accumulation of body fluids under the skin (subcutaneous) of the face (edema); ske...

L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle s...

Gastroesophogeal reflux (GER) is the upward flow of stomach contents from the stomach into the esophagus ("swallowing tube"). While not required by its definition, these contents may continue from the esophagus into the pharynx (throat) and may be...

Genital herpes, also known as herpes simplex virus type 2 (HSV-2), is a sexually transmitted infection that causes painful sores and blisters on the genital area. It is a chronic condition that can flare up periodically, causing symptoms such as i...

Congenital central hypoventilation syndrome (CCHS) is a rare disorder of respiratory control with autonomic nervous system dysregulation (ANSD). The autonomic nervous system is the portion of the nervous system that controls or regulates certain i...

Paroxysmal cold hemoglobinuria (PCH) is a rare type of anemia characterized by the premature destruction of healthy red blood cells by autoantibodies. The disorder is classified as an autoimmune hemolytic anemia (AIHA), an uncommon group of disord...

Hepatorenal syndrome (HRS) is a form of impaired kidney function that occurs in individuals with advanced liver disease. Individuals with hepatorenal syndrome do not have any identifiable cause of kidney dysfunction and the kidneys themselves are ...

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, ...

Holoprosencephaly (HPE) is the failure of the prosencephalon, or forebrain, to develop normally. The forebrain is a region of the brain in the fetus that develops into parts of the adult brain, including the cerebral cortex. Instead of the normal ...

Lamellar ichthyosis is a rare genetic skin disorder. In lamellar ichthyosis, the skin cells are produced at a normal rate, but they do not separate normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickl...

Dyspepsia (indigestion) facts Dyspepsia is a functional disease in which the gastrointestinal organs, primarily the stomach and first part of the small intestine, function abnormally. It is a chronic disease in which the symptoms fl...

Urticaria pigmentosa is a rare skin disorder that is a localized (cutaneous) form of mastocytosis. Some clinicians suggest that urticaria pigmentosa is the childhood form of mastocytosis. Mast cells are specialized cells of connective tissue that ...

Malignant carcinoid syndrome is characterized by a variety of signs and symptoms. Carcinoid tumors are neuroendocrine tumors that develop from primitive stem cells that can give rise to a variety of cell types. When a rare malignant...

Flesh-eating bacteria (necrotizing fasciitis) is a rare infection of the skin and tissues below it. It can be deadly if not treated quickly. Necrotizing fasciitis spreads quickly and aggressively in an infected person. It causes tissue dea...

Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes...

Pilonidal cyst facts Pilonidal cysts are fluid-filled sacs that form at the top of the crease of the buttocks above the sacrum. A painful abscess can form if the cyst and the overlying skin become infected. Pilonidal cysts...

General DiscussionWolff-Parkinson-White (WPW) syndrome is a rare congenital heart disorder involving irregularities in the electrical system of the heart. In individuals with WPW syndrome, an abnormal alternate electrical pathway (accesso...

Familial dysautonomia is a rare genetic disorder of the autonomic nervous system (ANS) that primarily affects people of Eastern European Jewish heritage. It is characterized by diminished sensitivity to pain, lack of overflow tearing in the eyes, ...

General DiscussionRomano-Ward syndrome is an inherited heart (cardiac) disorder characterized by abnormalities affecting the electrical system of the heart. The severity of Romano-Ward syndrome varies greatly from case to case. Some indiv...

Rosacea (roe-ZAY-she-uh) is a common skin condition that causes redness and visible blood vessels in your face. It may also produce small, red, pus-filled bumps. These signs and symptoms may flare up for a period of weeks to months and then dimini...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Reflex sympathetic dystrophy syndrome (RSDS), also known as complex regional pain syndrome, is a rare disorder of the sympathetic nervous system that is characterized by chronic, severe pain. The sympathetic nervous system is that part of the auto...

Systemic mastocytosis (mas-to-sy-TOE-sis) is a disorder that results in an excessive number of mast cells in your body. Mast cells normally help protect you from disease and aid in wound healing by releasing substances such as histamine and leukot...

What are yeast infections? What are commonly known as "yeast" infections are caused by various species of a yeast-like fungus called Candida, particularly the species Candida albicans. Yeast organisms are part of the germs (including bacte...

Toxoplasmosis (tok-so-plaz-MOE-sis) is a disease that results from infection with the Toxoplasma gondii parasite, one of the world's most common parasites. Infection usually occurs by eating undercooked contaminated meat, exposure from infected ca...

Gilbert syndrome is a mild genetic liver disorder in which the body cannot properly process bilirubin, a yellowish waste product that is formed when old or worn out red blood cells are broken down (hemolysis). Individuals with Gilbert syndrome hav...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

General DiscussionVACTERL association is a nonrandom association of birth defects that affects multiple median and para-median structures. The term VACTERL is an acronym with each letter representing the first letter of one of the more co...

L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle s...