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 articleBirt-Hogg-Dubé (BHD) syndrome also known as Hornstein–Knickenberg syndrome is a rare, autosomal dominantly inherited genodermatosis complex genetic monogenic skin disorder (genodermatosis) characterized by multiple cutaneous hamartomas (namely...
Read articleBiotinidase deficiency (BTD) is inherited via an autosomal recessive pattern via two pathogenic variants in the BTD gene, located at chromosome 3p25.1. BTD encodes for the biotinidase protein and enzyme,...
Read articleBinswanger disease also known as subcortical arteriosclerotic degeneration of the white matter encephalopathy is a progressive neurological chronic, uncontrolled, arterial hypertension disorder caused by arteriosclerosis and thromboembolism...
Read articleBinder-type nasomaxillary dysplasia also known as binder’s syndrome is a rare developmental defect that is present at birth (congenital) and characterized by a retruded mid-face with...
Read articleBiliary atresia is a rare gastrointestinal obstructive cholangiopathy disease of the intrahepatic or extrahepatic bile duct disorder characterized by the destruction or absence of all or...
Read articleBile acid synthesis disorders (BASDs) are a group of rare metabolic disorders characterized by defects in the creation (synthesis) of bile acids. Bile acids are chemical...
Read articleBest vitelliform macular dystrophy (BVMD) is a genetic rare autosomal dominant form of macular degeneration (damage to a part of the eye called the macula) that...
Read articleBerylliosis also known as chronic beryllium disease (CBD), is a granulomatous disease caused by exposure to beryllium a form of metal poisoning caused by inhalation of...
Read articleBernard-Soulier syndrome (BSS) is a rare autosomal-recessive inherited mucocutaneous bleeding disorder of blood clotting (coagulation) characterized by unusually large platelets, and unusually giant low platelet count (thrombocytopenia),...
Read articleBenign paroxysmal position vertigo (BPPV) is a peripheral perception of motion in the absence of movement disorder characterized by a brief, sensation of swaying, tilting, spinning,...
Read articleBenign essential blepharospasm (BEB) is a rare focal cranial dystonia neurological disorder characterized by involuntary contractions of orbicularis oculi muscle contractions, resulting in involuntary eye closure...
Read articleBejel is an infectious disease non-venereal tropical infectious disease caused by the organism Treponema pertenue that is rare in the United States but common in certain parts of...
Read articleBehçet’s syndrome also known as an oculo-orogenital syndrome, malignant aphthosis is a rare multisystem inflammatory chronic remitting and relapsing auto-inflammatory systemic vascular disorder of the eye...
Read articleBeckwith-Wiedemann syndrome (BWS) is the most common genetic imprinting, overgrowth, cancer predisposition, genetically and clinically heterogeneous disorder characterized by hemihypertrophy/lateralized overgrowth (LO), macroglossia, macrosomia, organomegaly, hyperinsulinism,...
Read articleBartter syndrome is a general term for a group of rare genetic autosomal recessive disorders of salt reabsorption resulting in extracellular fluid volume depletion with low/normal...
Read articleBartter syndrome is a general term for a group of rare genetic autosomal recessive disorders of salt reabsorption resulting in extracellular fluid volume depletion with low/normal...
Read articleBartonellosis is a group of gram-negative intracellular facultative bacterium emerging infectious diseases caused by bacteria belonging to the Bartonella genus. Bartonella includes at least 22 named species...
Read articleBarth syndrome is a genetic ultra-rare, infantile-onset, X-linked recessive metabolic mitochondrial disorder characterized by cardiomyopathy, neutropenia, skeletal myopathy, prepubertal growth delay, and distinctive facial gestalt (most...
Read articleBardet-Biedl syndrome (BBS) is a genetic rare autosomal recessive ciliopathy condition that impacts multiple body systems. It is characterized by heterogeneous clinical manifestations including primary features...
Read articleBarakat syndrome, also known as HDR syndrome is a clinically variable (heterogeneous), rare genetic disorder characterized by three characteristics: hypoparathyroidism (H) (decreased function of the parathyroid...
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