PKU Phenylketonuria, a metabolic disease that is due to the inherited inability to process the essential amino acid phenylalanine. The biochemical basis of PKU is complete or near-complete deficiency of the enzyme phenylalanine hydroxylase. Newborns in many countries are now routinely screened for PKU via a blood test. Treatment of PKU involves a special diet…
PKU, maternal The disease phenylketonuria (PKU) in a pregnant woman whose high blood levels of phenylalanine are dangerous to a developing fetus. High phe can damage a baby before birth. If the mother’s PKU is not controlled, the fetus (which may not have PKU) is at high risk for congenital heart disease, growth retardation, microcephaly,…
PKU, variant A form of phenylalanine hydroxylase deficiency that is more mild than classic PKU and typically causes less intellectual impairment.
phytochemical A plant compound that is thought to have health-protecting qualities. Also known as phytonutrient.
phytonutrient See phytochemical.
pia mater One of the meninges, the delicate innermost membrane that envelopes the brain and spinal cord. Known informally as the pia. See also meninges.
pianist’s cramp A dystonia that affects the muscles of the hand and sometimes the forearm, and that only occurs when one plays the piano or another keyboard instrument. Similar focal dystonias have also been called writer’s cramp, typist’s cramp, musician’s cramp, and golfer’s cramp.
pica A craving for something that is not normally regarded as nutritive, such as dirt, clay, paper, or chalk. Pica is a classic clue to iron deficiency in children, and it may also occur with zinc deficiency. Pica is also seen as a symptom in several neurobiological disorders, including autism and Tourette’s syndrome, and it…
Pick disease A form of dementia that is characterized by a slowly progressive deterioration of social skills and changes in personality, along with impairment of intellect, memory, and language. The common symptoms include loss of memory, lack of spontaneity, difficulty in thinking or concentrating, and disturbances of speech. Other symptoms can include gradual emotional dullness,…
Pickwickian syndrome A syndrome that is characterized by obesity, sleepiness, hypoventilation, and a reddened face. It occurs because of reduced blood oxygen levels due to breathing insufficiency. The syndrome is named for the “fat and red-faced boy in a state of somnolency” whom Charles Dickens described in his novel The Pickwick Papers. Also known as…
PID Pelvic inflammatory disease.
pigeon breast Having a prominent breastbone and chest. Also known as pectus carinatum.