Dictionary

polygenes Many genes. For example, eye color is polygenically controlled because many genes are involved in the determination of eye color.

polydipsia Constant, excessive drinking as a result of thirst. Polydipsia occurs in untreated or poorly controlled diabetes mellitus.

polydactyly More than the normal number of fingers or toes. The opposite of polydactyly is oligodactyly. See also hexadactyly.

polycythemia vera A disorder of the bone marrow that leads to overproduction of all three blood cell lines: white blood cells, red blood cells, and platelets. Its cause is unknown. Abbreviated PV. PV progresses slowly but may evolve into acute leukemia or myelofibrosis, in which the marrow is replaced by scar tissue. For a diagnosis…

polycythemia Too many red blood cells. The opposite of polycythemia is anemia. Polycythemia exists when the hemoglobin, red blood cell (RBC) count, and total RBC volume are all above normal. Polycythemia can lead to heart failure, stroke, and other medical problems when severe. Treatment can involve bloodletting. See polycythemia vera.

polycystic ovarian syndrome A hormonal problem, also known as polycystic ovarian disease, that causes women to have symptoms that include irregular or no menstruation, acne, obesity, and excess hair growth. Abbreviated PCOS. Women with PCOS do not ovulate (release an egg for fertilization) every month. They are at an increased risk for high blood pressure,…

polycystic kidney disease, autosomal recessive An early-onset disorder that is characterized by the presence of innumerable cysts in the kidneys and enlarged kidneys that can usually be detected via ultrasound before birth or in the neonatal period. Some cases are diagnosed later in childhood. The gene for the disease is on chromosome 6. Also known…

polycystic kidney disease, autosomal dominant The most common form of polycystic kidney disease characterized by the progressive development of innumerable cysts in the kidneys, causing hypertension, renal pain, and renal insufficiency (kidney failure). Other features of the disease can be cysts in other organs, such as the liver and pancreas, intracranial aneurysms, dilatation (widening) and…

polycystic kidney disease, adult See polycystic kidney disease, autosomal dominant.

Polycystic kidney disease (PKD) is an inherited disorder characterized by the growth of numerous fluid-filled cysts in the kidneys. These cysts gradually enlarge, replacing much of the normal kidney tissue, leading to kidney dysfunction and eventual kidney failure. Types of PKD Autosomal Dominant PKD (ADPKD) – The most common form, symptoms usually appear in adulthood…

polyarticular Involving many joints, as opposed to monoarticular (affecting just one joint).

polyarteritis nodosa An autoimmune disease that is characterized by spontaneous inflammation of the arteries (arteritis) and can affect any organ of the body. Polyarteritis nodosa most commonly affects muscles, joints, intestines, nerves, kidneys, and skin. Inflammation of the arteries can lead to inadequate blood supply and permanent damage to organs. Typically, polyarteritis nodosa is treated…