Phenylalaninemia (medical condition): A metabolic disorder where there is a deficiency of the enzyme phenylalanine hydroxylase which leads to a harmful buildup of the phenylalanine in the body. Normally the phenylalanine is converted into tyrosine. The severity of the symptoms can range from severe enough to cause mental retardation to mild enough not to require treatment. Severity is determined by the level of impairment of enzyme activity of phenylalanine hydroxylase.
Phenylketonuria (also known as Phenylalanine hydroxylase deficiency, and PKU) is an inborn error of metabolism involving impaired metabolism of the amino acid phenylalanine. Phenylketonuria is caused by absent or virtually absent phenylalanine hydroxylase (PAH) enzyme activity. The condition is also known as phenylalanine hydroxylase deficiency.
Protein-rich foods or the sweetener aspartame can act as poisons for people with phenylketonuria. The role of PAH is to break down excess phenylalanine from food. Phenylalanine is a necessary part of the human diet and is naturally present in all kinds of dietary protein. It is also used to make aspartame, known by the trade name Nutrasweet, which is used to sweeten low-calorie and sugar free soft drinks, yogurts, and desserts. In people without PKU, the PAH enzyme breaks down any excess phenylalanine from these sources beyond what is needed by the body. However, if there is not enough of the PAH enzyme or its cofactor, then phenylalanine can build up in the blood and brain to toxic levels, affecting brain development and function. PKU is rare, but important to identify, because if caught early it is very treatable. It is not contagious, and it is lifelong, but with early diagnosis and consistent treatment, the damaging effects can be minimal or non-existent.
Untreated PKU can lead to intellectual disability, seizures, and other serious medical problems. The best proven treatment for classical PKU patients is a strict phenylalanine-restricted diet supplemented by a medical formula containing amino acids and other nutrients. In the United States, the current recommendation is that the PKU diet should be maintained for life. Patients who are diagnosed early and maintain a strict diet can have a normal life span with normal mental development.
PKU is an inherited disease. When an infant is diagnosed with PKU, it is never the result of any action of the parents or any environmental factor. Rather, for a child to inherit PKU, both of his or her parents must have at least one mutated allele of the PAH gene. Most parents who are carriers of PKU genes are not aware that they have this mutation because being a carrier causes no medical problems. To be affected by PKU, a child must inherit two mutated alleles, one from each parent.
Phenylketonuria type 2: A genetic condition where phenylalanine (component of protein) is unable to be broken down due to an enzyme (phenylalanine hydroxylase) deficiency which leads to a harmful build up of the compound. The condition is characterized by neurological symptoms as well as the presence of increased levels of phenylalanine in the blood.
Phenylketonuric embryopathy (medical condition): A rare disorder where a mother suffering from phenylketonuria during pregnancy can result in various birth abnormalities.
Pheochromocytomas are tumors of the adrenal gland which produce excess adrenaline. Pheochromocytomas arise from the central portion of the adrenal gland which is called the adrenal medulla. The adrenal medulla is responsible for the normal production of adrenaline which our body requires to help maintain blood pressure and to help cope with stressful situations. A tumor which arises from the adrenal medulla and overproduces adrenaline can be a deadly tumor because of the severe elevation in blood pressure it causes.
Pheochromocytoma as part of Neurofibromatosis: A tumor that develops in the part of the adrenal gland called the medulla which produces adrenalin and noradrenaline. This tumor is often associated with a condition called neurofibromatosis. The tumor affects automatic body activities such as regulating breathing rate and heartbeat.
Philadelphia-negative chronic myeloid leukemia is a slow-developing cancer of the bone marrow and blood in which the body produces an uncontrolled number of abnormal white blood cells. More than 90% of cases result from a cytogenetic aberration known as the Philadelphia chromosome (Philadelphia-positive chronic myeloid leukemia). For Philadelphia-negative chronic myeloid leukemia, the exact cause of the disease is not known. Although a variety of medications have been used in chronic myeloid leukemia, including myelosuppressive agents and interferon alpha, the tyrosine kinase inhibitor imatinib mesylate is currently the agent of choice, and other drugs in this category are playing increasingly important roles. However, allogeneic bone marrow transplantation is currently the only proven cure for chronic myeloid leukemia.
Phocomelia - contractures - absent thumb: A very rare syndrome characterized mainly by absent thumbs, contractures and missing arm and leg bones.
Phocomelia syndrome:- Phocomelia is a congenital disorder involving the limbs (dysmelia). An individual exhibiting phocomelia may be referred to as a phocomelus.
Phosphate diabetes: A condition where the kidney tubules fail to reabsorb phosphate resulting in excess phosphate in the urine.
Phosphoglucomutase deficiency: An enzyme (phosphoglucomutase) deficiency which causes metabolic problems.
Phosphoglucomutase deficiency: An enzyme (phosphoglucomutase) deficiency which causes metabolic problems.
Phosphoglucomutase deficiency: An enzyme (phosphoglucomutase) deficiency which causes metabolic problems.
Phosphoglucomutase deficiency: An enzyme (phosphoglucomutase) deficiency which causes metabolic problems.
Phosphoglucomutase deficiency: An enzyme (phosphoglucomutase) deficiency which causes metabolic problems.
Phosphoglycerate kinase 1 deficiency: An inherited genetic muscle disease where an enzyme deficiency (phosphoglycerate kinase) affects the normal processes that convert carbohydrates from food into energy.
Phosphoglycerate kinase deficiency is a hereditary metabolic muscle disease. There are two distinct syndromes. There is a pure muscle syndrome characterized by recurrent cramps and muscle breakdown in response to intense exercise, and a "muscle plus" syndrome which may feature mental retardation and/or haemolytic anaemia. Phosphoglycerate kinase is a complex enzyme. Several subtypes of phosphoglycerate kinase deficiency have been identified,1 based on the tissues in which the enzyme deficiency occurs, and the type of inheritance.
Phosphomannose isomerase deficiency: Another name for Congenital disorder of glycosylation type 1B (or close medical condition association). Congenital disorder of glycosylation type 1B:
Phosphoribosylpyrophosphate synthetase deficiency: A rare disorder where an enzyme (Phosphoribosylpyrophosphate synthetase) deficiency causes mental retardation and hypouricemia.
Photosensitive epilepsy is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights, bold, regular patterns, or regular moving patterns.
Phyllodes tumor of the prostate: A rare type of tumor that occurs in the prostate. The tumor is usually benign but may become malignant and tends to have a leaf-like appearance.
Phyllodes tumors (or phylloides tumors) are rare breast tumors that start in the connective (stromal) tissue of the breast, not the ducts or glands (which is where most breast cancers start). Most phyllodes tumors are benign and only a small number are malignant (cancer).
Phyllodes tumors are most common in women in their 40s, but women of any age can have them. Women with Li-Fraumeni syndrome (a rare, inherited genetic condition) have an increased risk for phyllodes tumors.
Phyllodes tumors are often divided into 3 groups, based on how they look under a microscope:
Phytanic acid oxidase deficiency (medical condition): A metabolic disorder where a deficiency of phytanic acid alpha-hydroxylase results in a buildup of phytanic acid in the body which causes neurological disorders.
PIBIDS syndrome: A rare inherited skin disorder characterized by photosensitivity (P), red, dry, scaly skin (I - ichthyosis), brittle hair (B), impaired physical and mental development (I), decreased fertility (D) and short stature (S). It is the same as IBIDS syndrome but involves photosensitivity.
Picardi-Lassueur-Little syndrome: A very rare disorder characterized by patches of hair loss involving the scalp, armpits, eyebrows and genitals. The hair loss on the scalp is accompanied by scarring of the skin. Hair follicles become eruptive and spiny usually months to years after hair loss.
Pick disease is a brain disorder that causes slowly worsening decline of mental abilities. It gradually damages brain cells and impairs their function. It disturbs cognitive processes, such as reasoning, problem solving, and memory. The disease often affects a person’s ability to use and understand spoken, written, and even signed language. It also affects personality, emotions, and social behavior. When the decline in mental abilities is severe enough to interfere with a person’s ability to carry out everyday activities, it is called dementia. Pick disease is named after Arnold Pick, the doctor who first described the disease in 1892. It is often compared to Alzheimer disease. However, Pick disease is different from Alzheimer disease in several ways. * First, the diseases affect different parts of the brain. Pick disease usually affects only the frontal and temporal lobes of the brain, the part from the forehead back to the ears. For this reason it is sometimes called “frontotemporal dementia.” Pick disease is only one of several types of frontotemporal dementia. * * Second, the diseases damage the brain in different ways. The changes they cause in the brain are distinct. Both diseases cause severe shrinkage (atrophy) of brain tissue and death of nerve cells called neurons. In Pick disease, the neurons contain abnormal protein accumulations called Pick bodies. Neurons may swell as they stop functioning. * * These differences translate to somewhat different symptoms for the two diseases. Memory loss, usually the first symptom in Alzheimer disease, may not occur in Pick disease until later in the disease. People with Pick disease may have early changes in mood, behavior, and use of language and speech (aphasia). * * On average, Pick disease occurs at a somewhat younger age than Alzheimer disease. In Pick disease, the first symptoms typically appear in middle age, in people aged 40-60 years. However, it can occur in adults of any age. Unfortunately, Pick disease is similar to Alzheimer disease in several ways. * It is a progressive disease, meaning that the symptoms gradually worsen over time and do not get better. * * The two diseases are equally devastating, causing gradual decline of mental functions and disability. * * Neither disease is curable. Much less is known about Pick disease than about Alzheimer disease. This is partly because Pick disease is a much less common disease. Also, Pick bodies and neuron swelling are difficult to detect in a living person, so Pick disease may go undiagnosed or be misdiagnosed. People with Pick disease are sometimes thought to have Alzheimer disease. This is changing as medical professionals learn more about Pick disease.
Piebaldism: A rare genetic condition characterized by patches of lack of pigmentation that involves the skin and the hair.