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 articlePatau’s syndrome, also called trisomy 13, is a genetic problem that starts when a baby is still a tiny group of cells. In this condition there...
Read articleComplete trisomy 13 syndrome (also called Patau syndrome) is a genetic condition where every cell in the baby’s body has three copies of chromosome 13 instead...
Read articleComplete endocardial cushion defect is a birth heart problem in which there is a big hole in the center of the heart and only one large...
Read articleComplete atrioventricular septal defect with atrial and ventricular components (complete AVSD) is a birth heart problem where there is one large hole in the center of...
Read articleComplete atrioventricular canal defect is a serious heart problem that a baby is born with. In this condition there is one large hole in the middle...
Read articleComplete atrioventricular canal is a serious heart problem that a baby is born with. In this condition there is a big hole in the center of...
Read articleComplete androgen resistance syndrome means the body cannot “hear” or use male sex hormones (androgens) at all, even though these hormones are present in normal or...
Read articleComplement receptor deficiency is a rare health problem where the body does not have enough working “complement receptors” on its immune cells, or these receptors do...
Read articleComplement component deficiency is a health problem where one or more proteins of the “complement system” are missing or do not work properly. [1] The complement...
Read articleComplement deficiency caused by mutation in C5 (also called complement component 5 deficiency or C5 deficiency) is a rare problem of the immune system. In this...
Read articleComplement component 5 deficiency (often shortened to C5 deficiency or C5D) is a rare problem of the immune system where the body does not have enough...
Read articleClassic complement early component deficiency caused by mutation in C3 means that an important immune protein, called complement component 3 or C3, is missing or does...
Read articleC3 complement deficiency means that the blood has very low or almost no working C3 protein, which is one of the main “helper” proteins in the...
Read articleComplement component 3 (C3) deficiency is a health problem where the blood has very low or almost no C3 protein, which is a key part of...
Read articleComplement deficiency caused by mutation in C2 means that a small change (mutation) in the C2 gene stops the body from making enough working C2 protein,...
Read articleComplement component 2 deficiency (often called “C2 deficiency”) is a problem in the immune system. In this condition, the body does not have enough working complement...
Read articleCompartment syndrome is a serious problem that happens when pressure inside a closed space in the body (a “compartment”) becomes too high. Muscles, nerves, and blood...
Read articleSporadic hypogammaglobulinemia is a health problem where the body has low levels of protective proteins called immunoglobulins (antibodies), even though there is no clear family history...
Read articleCommon variable agammaglobulinemia is usually used to describe common variable immunodeficiency (CVID) – a primary immune system disease where the body makes very low levels of...
Read articleCommon variable immunodeficiency (usually called CVID) is a long-term problem of the immune system. In CVID, the body does not make enough protective proteins called antibodies...
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