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 articleDeficiency of hexose-1-phosphate uridylyltransferase means that the body has very low or no activity of an enzyme called galactose-1-phosphate uridylyltransferase (GALT). This enzyme normally helps change...
Read articleDeficiency of galactose-1-phosphate uridyl transferase (usually written GALT deficiency) is a genetic disease where the body is missing, or has very low activity of, an enzyme...
Read articleClassic galactosemia is a rare genetic disease that affects how the body uses a sugar called galactose, which is found in milk and many milk-based foods....
Read articleClassic familial adenomatous polyposis is an inherited disease where a person grows hundreds to thousands of small growths, called polyps, inside the large intestine (colon) and...
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 articleClassic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is a genetic disease that affects the adrenal glands, which are small organs that sit on top...
Read articleAutosomal dominant intellectual disability 49 is a very rare genetic brain-development problem. It is also called Clark-Baraitser syndrome and is caused by a change (mutation) in...
Read articleClark-Baraitser syndrome (often shortened to CLABARS) is a very rare genetic condition that affects how a child’s brain, body growth, and face develop. Children usually have...
Read articleCLAPO syndrome is a very rare health condition that mostly affects the skin, blood vessels, lymph vessels, and the growth of some body parts. The name...
Read articleX-linked intellectual disability–microcephaly–cortical malformation–thin habitus syndrome is a very rare genetic disease that mainly affects boys. Doctors also call it CK syndrome. In this condition, the...
Read articleCK syndrome is a very rare genetic brain and body disorder that mainly affects boys and starts in early life. It is an X-linked recessive condition,...
Read articleAdult-onset citrin deficiency is a rare, lifelong genetic disease that mainly affects the liver and the brain. In this condition, a gene called SLC25A13 does not...
Read articleCitrullinemia type II is a rare inherited disease in which the liver cannot use a substance called citrin properly, so ammonia and some amino acids build...
Read articleArgininosuccinate synthetase deficiency (ASS1 deficiency) is a rare, inherited disease of the urea cycle. The urea cycle is the process in the liver that changes extra...
Read articleArgininosuccinate synthase 1–gene related citrullinemia type I is a rare, serious genetic disease of the urea cycle. In this disease the ASS1 gene does not work...
Read articleCitrullinemia type I is a rare inherited disease of the urea cycle, which is the process in the liver that removes extra nitrogen from the body....
Read articleDystonia-parkinsonism-hypermanganesemia-polycythemia and chronic liver disease is a very rare inherited disease. In this condition, a gene called SLC30A10 does not work properly. Because of this, the...
Read articleCirrhosis–dystonia–polycythemia–hypermanganesemia syndrome is a very rare genetic disease where the body cannot properly remove extra manganese, a metal that is normally needed in very small amounts....
Read articleCiliary dyskinesia with transposition of ciliary microtubules is a rare genetic problem that affects tiny hair-like structures in the body called cilia. Cilia sit on the...
Read articleFamilial partial lipodystrophy type 5 (FPLD5) is a very rare genetic disease where fat under the skin (subcutaneous fat) is lost from some parts of the...
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