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 articleCongenital analbuminemia is a very rare inherited disease in which the body makes almost no normal albumin, or makes an extremely tiny amount of it. Albumin...
Read articleCongenital hypofibrinogenemia is a rare blood problem that a person is born with. In this condition, the blood has a lower-than-normal level of a protein called...
Read articleCongenital afibrinogenemia is a rare inherited bleeding disorder where the body makes almost no fibrinogen, which is also called coagulation factor I. Fibrinogen is a protein...
Read articleCongenital adrenal insufficiency with 46,XY sex reversal (also called 46,XY disorder of sex development with adrenal insufficiency due to CYP11A1 deficiency) is a rare genetic disease....
Read articleCongenital acardia means a baby is formed inside the womb without a working heart or with almost no heart at all. This rare problem almost always...
Read articleComplete phocomelia of the upper limb is a birth problem where almost the whole arm is missing, and the hand is attached very close to the...
Read articleCongenital absence of the thigh and leg means that a baby is born with most or all of the bones of the upper leg (thigh bone...
Read articleComplete phocomelia of the lower limb is a birth defect where the thigh bone and the bones of the lower leg are completely missing, but the...
Read articleCongenital absence of thigh and lower leg with foot present is a birth defect where the baby is born without the thigh bone (femur) and the...
Read articleCongenital aplasia of the lacrimal gland co-occurrent with congenital aplasia of the salivary glands means that a baby is born without the normal tear-making glands (lacrimal...
Read articleCongenital absence of the salivary gland means a baby is born without one or more salivary glands. Doctors also call this salivary gland aplasia or salivary...
Read articleTransverse deficiency of the lower limb is a birth difference where the leg grows normally up to a certain level, and everything beyond that level is...
Read articleCongenital absence of both lower leg and foot means a baby is born without the lower part of both legs and without both feet. The bones...
Read articleProgressive cone-rod dystrophy caused by mutation in GUCY2D is a rare, inherited eye disease that slowly damages the light-sensing cells (photoreceptors) in the retina, especially the...
Read articleCone-rod dystrophy caused by mutation in the PITPNM3 gene (sometimes called CORD5) is a rare inherited eye disease. It mainly damages cone cells in the center...
Read articleCone-rod dystrophy type 5 (often written as CORD5) is a very rare, inherited eye disease that slowly damages the light-sensing cells in the back of the...
Read articleCone-rod dystrophy type 3, also called CORD3, is a rare inherited retinal disease. It mainly damages the cone cells first, and then the rod cells become...
Read articleCone-rod retinal dystrophy type 1, often shortened to CORD1, is a rare inherited eye disease. It belongs to the larger cone-rod dystrophy family. In this disease,...
Read articleCone-rod dystrophy 1 (often related to changes in the CDHR1 gene) is a rare inherited eye disease. It slowly damages the cone cells (used for sharp...
Read articleIncomplete achromatopsia is a rare, inherited eye condition where cone cells in the retina partly work but not normally. People usually have reduced vision, very strong...
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