A protective gene that normally limits the growth of tumors. When a tumor suppressor gene is mutated (altered), it may fail to keep a cancer from growing. BRCA1, an example of a tumor suppressor gene, was the first breast cancer gene to be identified; mutated forms of this gene are responsible for some cases of […]
surgery (to take out the cancer); radiation therapy (using high-dose x-rays to kill the cancer cells); biological therapy (using the body’s natural immune system to fight the cancer); and chemotherapy (using drugs to kill cancer cells). Carcinoid tumors are considered a type of endocrine tumor since they secrete a hormone (serotonin). They can occur as […]
Benign (noncancerous) bumps on the pinna of the ear (the external ear) or within the external ear canal. Most of these lumps and bumps are just harmless cysts and tumors. However, some of the bumps are bony overgrowths (known as exostoses or osteomas). If they are large and interfere with hearing, they can be surgically […]
The examination of fluid from a bulla (a blister) in search of Tzanck cells characteristic of varicella (chickenpox), herpes zoster, herpes simplex, and pemphigus vulgaris. Named for a Russian dermatologist Arnault Tzanck (1886-1954).
A metabolic genetic disease due to deficiency of the enzyme tyrosine transaminase. The disease is characterized by the deposition of crystals of tyrosine in the skin and eyes. Thickened areas (keratoses) on the palms and soles become painful and ulcers develop in the cornea. There is often mental retardation in tyrosinemia type II. It is […]
A metabolic genetic disease characterized by abnormally high levels of amino acid tyrosine in blood (hypertyrosinemia) and urine (tyrosinuria) due to deficiency of an enzyme called fumarylacetoacetic hydrolase, the last enzyme in the tyrosine pathway. Tyrosinemia type I is inherited as an autosomal recessive disorder. The disease causes cirrhosis of the liver before 6 months […]
A genetic disorder involving the metabolism of the amino acid tyrosine characterized by abnormally high levels of tyrosine in blood (hypertyrosinemia) and urine (tyrosinuria). There are several different forms of tyrosinemia. The classic form, tyrosinemia type I, is due to deficiency of an enzyme called fumarylacetoacetic hydrolase, the last enzyme in the tyrosine pathway. Although […]
A dystonia that affects the muscles of the hand and sometimes the forearm and only occurs during handwriting. Similar focal dystonias have also been called writer’s cramp, pianist’s cramp, musician’s cramp, and golfer’s cramp.
Murine typhus, an acute infectious disease with fever, headache, and rash, all quite similar to, but milder than, epidemic typhus. It is caused by a related microorganism, Rickettsia typhi (mooseri), transmitted to humans by rat fleas (Xenopsylla cheopis). The animal reservoir includes rats, mice and other rodents. Murine typhus occurs sporadically worldwide but is more […]
Also known as Rocky Mountain spotted fever, an acute febrile (feverish) disease initially recognized in the Rocky Mountain states, caused by Rickettsia rickettsii transmitted by hard-shelled (ixodid) ticks. Occurs only in the Western Hemisphere. In the USA it is most common in the southeastern and south-central states, not in the Rocky Mountains. Anyone frequenting tick-infested […]