Browse plain-English disease and condition guides, including symptoms, causes, diagnosis, treatment options, prevention, and when to seek medical care.
Anal Anomalies–Porokeratosis Syndrome, often referred to as AAPS, is a rare medical condition that affects various aspects of a person’s health. In this comprehensive article, we...
Read article11β-HSD2 deficiency is a rare genetic condition in which the body cannot properly switch the hormone cortisol into its inactive form, cortisone, inside certain kidney cells....
Read article1p36 microdeletion syndrome (also called 1p36 deletion syndrome) is a genetic condition that starts before birth. A small piece of chromosome 1, from the short arm...
Read article1q21.1 deletion syndrome (also called 1q21.1 microdeletion) is a genetic disorder caused by the loss of a small segment of DNA on the long arm (q...
Read article1q21.1 duplication syndrome (also called 1q21.1 microduplication) is a chromosomal copy-number variant in which a small segment of genetic material on the long (q) arm of...
Read article1q21.1 recurrent microdeletion is a tiny missing piece of DNA on chromosome 1, at a place called “1q21.1.” In this condition, one copy of chromosome 1...
Read article2-methylacyl-CoA racemase deficiency is a very rare inherited metabolic disease. It happens when the body does not make enough working AMACR enzyme. This enzyme helps break...
Read article2,8-dihydroxyadenine (DHA) urolithiasis is a rare form of kidney stone disease. It happens when the body cannot recycle the purine base adenine in the normal “salvage”...
Read article2,8-dihydroxyadeninuria is a rare, inherited problem of purine recycling. Your body normally reuses adenine (a building block of DNA) using an enzyme called APRT (adenine phosphoribosyltransferase)....
Read article21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) is a genetic disease that affects how the adrenal glands make important hormones called cortisol and aldosterone. The adrenal glands are...
Read article3-beta-hydroxy-delta-5-c27-steroid dehydrogenase deficiency is a very rare inherited liver disease. It is one of the bile acid synthesis disorders. In this condition, the liver cannot make...
Read article3-methylglutaconic aciduria type 2 is a rare, inherited condition that almost always affects boys. It is also called Barth syndrome. It happens because of a change...
Read articleAlveolar capillary dysplasia with misalignment of the pulmonary veins (ACDMPV, OMIM# 265380) is a rare disorder present at birth (congenital). Infants experience severe, life-threatening breathing problems...
Read articleAlternating hemiplegia of childhood (AHC) is a rare neurodevelopmental transient episode of hemiplegia alternating in the laterality or quadriparesis, nystagmus, and other paroxysmal attacks tonic and...
Read articleAlström syndrome is a rare complex genetic disorder that is associated with a wide variety of symptoms affecting multiple organ systems of the body. The disorder...
Read articleAlport syndrome is a rare genetic also known as hereditary nephritis is a genetic disorder arising from the mutations in the genes encoding alpha-3, alpha-4, and...
Read articleAlpha-mannosidosis is a rare genetic disorder characterized by a deficiency of the enzyme alpha-D-mannosidase. Alpha-mannosidosis is best thought of as a continuum of diseases that is...
Read articleAlpha-1 antitrypsin deficiency (A1AD) is a clinically under-recognized hereditary genetic disorder that causes the defective production of alpha-1 antitrypsin protein and AAT protein protects the body...
Read articleAlpha thalassemia X-linked intellectual disability (ATR-X) syndrome is a rare genetic disorder affecting multiple organ systems of the body. ATR-X syndrome is characterized by intellectual disability,...
Read articleAlpha thalassemia is a general term for a group of inherited blood disorders characterized by reduced or absent production of alpha-globin subunits, resulting in low levels...
Read articleAlpers disease is a progressive neurologic disorder that begins during childhood and is complicated in many instances by serious liver disease associated with mutations in the...
Read articleAlopecia areata is a form of alopecia that impacts hair follicles, nails, and rarely, the retinal pigment epithelium and typically presents with round patches and is...
Read articleAlexander disease is an extremely rare, autosomal dominant leukodystrophy, which is a neurological condition caused by anomalies in the myelin which protects nerve fibers in the...
Read articleAlagille syndrome (ALGS) also known as arteriohepatic dysplasia is a rare genetic multisystem disease characterized by cholestasis and bile duct paucity on liver biopsy in addition...
Read articleALAD porphyria is a very rare genetic metabolic disease characterized by an almost complete deficiency of the enzyme delta-aminolevulinic acid (ALA) dehydratase. The deficiency of this...
Read articleThe term “AIDS dysmorphic syndrome” or “HIV embryopathy” has been used by some researchers to describe specific facial malformations (i.e., craniofacial dysmorphism), an unusually small head,...
Read articleAicardi syndrome is also known as agenesis of the corpus callosum with chorioretinitis abnormality, agenesis of the corpus callosum with infantile spasms and ocular anomalies, callosal...
Read articleAhumada-Del Castillo is a rare endocrine disorder affecting adult females, which is characterized by impairment in the function of the pituitary and hypothalamus glands. Symptoms may...
Read articleAcquired agranulocytosis is rare, also known as agranulosis or granulopenia, a drug-induced blood disorder that is characterized by a severe reduction in the number of white...
Read articleAgenesis of corpus callosum (ACC) is a rare birth defect in which there is a complete or partial absence of the corpus callosum that is present...
Read articleAn agammaglobulinemia is a group of inherited immune deficiencies characterized by a low concentration of antibodies in the blood due to the lack of particular lymphocytes...
Read articleAfrican iron overload also known as Bantu siderosis or dietary iron overload is a rare disorder characterized by abnormally elevated levels of iron in the body. The...
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