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 articleCOACH syndrome is a very rare genetic disease that mainly affects the brain, liver, eyes, and sometimes the kidneys. It is an autosomal recessive condition, which...
Read articleCongenital lipomatous overgrowth-vascular malformation-epidermal nevi-spinal anomaly syndrome is usually called CLOVES syndrome. It is a very rare birth condition where a baby is born with too...
Read articleCongenital lipomatous overgrowth-vascular malformation-epidermal nevi-skeletal anomaly syndrome is usually called CLOVES syndrome. It is a very rare birth problem. Babies are born with too much soft...
Read articleCLOVES syndrome is a very rare disease where some parts of the body grow too much and in an uneven way. It usually starts before birth,...
Read articleOmphalocele–cloacal exstrophy–imperforate anus–spinal defect syndrome is usually called OEIS complex. It is a very rare birth condition where a baby is born with four main problems...
Read articleWallis-Zieff-Goldblatt syndrome is an extremely rare genetic bone growth problem. It mainly affects the bones near the shoulders and the upper arms, and also the collarbones...
Read articleMcPherson-Clemens syndrome (also called cleft lip/palate–intestinal malrotation–cardiopathy syndrome) is an extremely rare genetic disorder that affects many parts of a baby’s body from birth. It is...
Read articleZlotogora-Zilberman-Tenenbaum syndrome is an extremely rare genetic condition in which the outer layer of the body (skin, hair, nails, teeth, some glands) and parts of the...
Read articleZlotogora-Ogur syndrome is a very rare genetic disease that mainly affects body parts made from the outer layer of the embryo (the ectoderm), such as skin,...
Read articleCleft lip/palate-ectodermal dysplasia syndrome is a very rare genetic condition. In this syndrome, a baby is born with a split in the upper lip and/or the...
Read articleLowry-Yong syndrome is a very rare genetic condition that is present from birth and mainly affects the face, hearing system, lower spine, and some bones of...
Read articleAusems Wittebol-Post Hennekam syndrome is an extremely rare genetic condition where a child is born with a cleft lip and slowly worsening disease of the light-sensing...
Read article4-layered lissencephaly is a “smooth brain” condition where the outer part of the brain (the cerebral cortex) does not form normal folds (gyri) and grooves (sulci),...
Read articleClassic lissencephaly (also called type 1 lissencephaly) is a rare brain problem that starts before birth, when the baby is still in the womb. In this...
Read articleHyperhomocysteinemic syndrome means a person has too much homocysteine in the blood, usually above about 15 micromoles per liter (µmol/L). [1] Homocysteine is a normal amino...
Read articleHomocystinuria due to cystathionine beta-synthase (CBS) deficiency is a rare genetic disease where the body cannot properly break down the amino acid methionine. Because the CBS...
Read articleHomocystinuria caused by cystathionine beta-synthase deficiency is a rare genetic disease. In this condition, the body cannot use an amino acid called methionine in the normal...
Read articleDeficiency of serine sulfhydrase means that a special body enzyme called cystathionine-beta-synthase (CBS) does not work properly or is missing. This enzyme normally changes two amino...
Read articleClassic homocystinuria is a rare genetic disease where the body cannot break down an amino acid called homocysteine properly because an enzyme named cystathionine beta-synthase (CBS)...
Read articleTransferase deficiency galactosemia type 1 (often called classic galactosemia) is a rare genetic disease where the body cannot properly break down a milk sugar called galactose....
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