Primary localized cutaneous amyloidosis (PLCA) is a condition in which clumps of abnormal proteins called amyloids build up in the skin, specifically in the wave-like projections (dermal papillae) between the top two layers of skin (the dermis and th READ MORE

Primary macronodular adrenal hyperplasia (PMAH) is a disorder characterized by multiple lumps (nodules) in the adrenal glands, which are small hormone-producing glands located on top of each kidney. These nodules, which usually are found in both adre READ MORE

Primary myelofibrosis is a condition characterized by the buildup of scar tissue (fibrosis) in the bone marrow, the tissue that produces blood cells. Because of the fibrosis, the bone marrow is unable to make enough normal blood cells. The shortage o READ MORE

Primary sclerosing cholangitis is a condition that affects the bile ducts. These ducts carry bile (a fluid that helps to digest fats) from the liver, where bile is produced, to the gallbladder, where it is stored, and to the small intestine, where it READ MORE

Primary spontaneous pneumothorax is an abnormal accumulation of air in the space between the lungs and the chest cavity (called the pleural space) that can result in the partial or complete collapse of a lung. This type of pneumothorax is described a READ MORE

Prion disease represents a group of conditions that affect the nervous system in humans and animals. In people, these conditions impair brain function, causing changes in memory, personality, and behavior; a decline in intellectual function (dementia READ MORE

Progressive external ophthalmoplegia is a condition characterized by weakness of the eye muscles. The condition typically appears in adults between ages 18 and 40 and slowly worsens over time. The first sign of progressive external ophthalmoplegia is READ MORE

Progressive familial heart block is a genetic condition that alters the normal beating of the heart. A normal heartbeat is controlled by electrical signals that move through the heart in a highly coordinated way. These signals begin in a specialized READ MORE

Progressive familial intrahepatic cholestasis (PFIC) is a disorder that causes progressive liver disease, which typically leads to liver failure. In people with PFIC, liver cells are less able to secrete a digestive fluid called bile. The buildup of READ MORE

Progressive myoclonic epilepsy type 1 (also called Unverricht-Lundborg disease or ULD) is a rare inherited form of epilepsy. Early development is normal in affected individuals. Signs and symptoms of the disorder typically begin between 6 and 15 year READ MORE

Progressive osseous heteroplasia is a disorder in which bone forms within skin and muscle tissue. Bone that forms outside the skeleton is called heterotopic or ectopic bone. In progressive osseous heteroplasia, ectopic bone formation begins in the de READ MORE

Progressive pseudorheumatoid dysplasia (PPRD) is a joint disease that worsens over time. This condition is characterized by breakdown (degeneration) of the cartilage between bones (articular cartilage). This cartilage covers and protects the ends of READ MORE