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 articleBanti syndrome is a disorder of the spleen, the large, gland-like organ in the upper left side of the abdomen that produces red blood cells before...
Read articleBannayan-Riley-Ruvalcaba syndrome (BRRS) also known as Bannayan-Zonana syndrome, Riley-Smith syndrome, and Ruvalcava-Myhre-Smith syndrome is a rare genetic overgrowth syndrome and hamartomatous with the occurrence of multiple subcutaneous lipomas, macrocephaly and hemangiomas disorder that...
Read articleBalo Disease is also known as Balo disease, encephalitis periaxialis concentrica, leukoencephalitis periaxialis concentric and concentric sclerosis are rare and progressive variants of multiple sclerosis. It...
Read articleBaller-Gerold syndrome (BGS) also referred to as craniosynostosis-radial aplasia syndrome is a rare genetic disorder that is characterized by craniosynostosis, particularly of the coronal sutures, a...
Read articleBalantidiasis is a rare intestinal infection caused by the bacterium, Balantidium coli, a single-celled parasite (ciliate protozoan) that frequently infects pigs but on occasion (rarely) infects...
Read articleBabesiosis is a rare infectious disease caused by single-celled microorganisms (protozoa) belonging to the Babesia family. Babesiosis is an infectious disease caused by intraerythrocytic, tick-borne protozoa...
Read articleAxenfeld-Rieger syndrome (ARS) is a rare genetic disorder that encompasses anterior segment ocular dysgenesis in addition to systemic abnormalities such as dental, cardiac, craniofacial, and abdominal...
Read articleAutosomal recessive polycystic kidney disease (ARPKD) is a rare genetic disorder characterized by the formation of fluid-filled sacs (cysts) in the kidneys. Most affected infants have...
Read articleAutosomal recessive hypophosphatemic rickets type 2 (ARHR2) is a skeletal condition that is characterized by rickets, bone pain, bone deformities, increased risk of bone fractures, fatigue,...
Read articleAutosomal dominant hyper IgE syndrome (AD-HIES) is a rare multisystem primary immunodeficiency disorder distinguished by the clinical triad of atopic dermatitis, recurrent skin staphylococcal infections, and...
Read articleNeonatal hyperglycemia is usually defined as serum glucose greater than 150 mg/dl (8.3 mmol/L) or whole blood glucose greater than 125 mg/dl (6.9 mmol/L) irrespective of...
Read articleColitis is inflammation of the mucosal lining of the colon which may be acute or chronic. Colitis is common and increasing in prevalence worldwide. Patients with...
Read articleAutoinflammation with infantile enterocolitis (AIFEC) is a newly identified and extremely rare inflammatory disorder that manifests early in infancy and affects patients throughout adulthood. AIFEC is...
Read articleAutoimmune polyglandular syndrome type 1 (APS-1) is a rare and complex recessively inherited disorder of immune-cell dysfunction with multiple autoimmunities. It presents as a group of...
Read articleAutoimmune polyendocrine syndrome type II, also known as Schmidt syndrome, clusters of endocrine abnormalities is a rare autoimmune disorder in which there is a steep drop...
Read articleAutoimmune blistering diseases are a group of disorders in which the body mistakenly attacks healthy tissue, causing blistering lesions that primarily affect the skin and mucous...
Read articleAuditory neuropathy spectrum disorder (ANSD) is a newly described condition defined as a sensorineural hearing loss that affects a person’s ability to hear or understand speech....
Read articleAtrioventricular septal defect (ASVD) is a general term for a group of rare heart defects that are present at birth (congenital). Infants with ASVDs have improperly...
Read articleAtrial septal defects (ASDs) are a group of rare disorders of the heart that are present at birth (congenital) and involve a hole in the wall...
Read articleAtransferrinemia is an extremely rare genetic disorder characterized by low levels of healthy, functional red cells in the blood (hypochromic, microcytic anemia) and by the accumulation...
Read article
