Disease – Page 174 – CheckOrphan

Pyridoxamine 5′-phosphate oxidase deficiency

The PNPO gene provides instructions for producing an enzyme called pyridoxine 5′-phosphate oxidase. This enzyme is involved in the breakdown (metabolism) of vitamin B6. Specifically, it chemically modifies two forms of vitamin B6 derived from food (pyridoxine and pyridoxamine) to form pyridoxal 5′-phosphate (PLP). PLP is the active form of vitamin B6 and is necessary for many processes in the body, including protein metabolism and the production of chemicals that transmit signals in the brain (neurotransmitters). Pyridoxine 5′-phosphate oxidase is active (expressed) in cells throughout the body, with the highest amounts found in the liver.

At least 7 mutations in the PNPO gene have been found to cause pyridoxal 5′-phosphate-dependent epilepsy. Most of these mutations change one protein building block (amino acid) in the pyridoxine 5′-phosphate oxidase enzyme, impairing its normal function. The resulting enzyme cannot effectively metabolize pyridoxine and pyridoxamine to produce PLP. A shortage of PLP can disrupt the function of many other proteins and enzymes that need PLP in order to be effective. It is not clear how the lack of PLP affects the brain and leads to the seizures that are characteristic of this condition.

Pyridoxine deficiency

Pyridoxine deficiency (also known as B6 deficiency) is a paediatric disease due to a lack of pyridoxine (or vitamin B6). The disease presents with several key symptoms including seizures, irritability, cheilitis (inflammation of the lips), conjunctivitis and neurologic symptoms. It usually becomes noticeable within the first 12 months of life in infants with a lack of pyridoxine, a coenzyme responsible for numerous essential metabolic reactions in humans. It is rarely observed, even in undeveloped countries.[1][2]

Pyridoxine-dependent epilepsy

Pyridoxine-dependent epilepsy is a condition that involves seizures beginning in infancy or, in some cases, before birth. Those affected typically experience prolonged seizures lasting several minutes (status epilepticus). These seizures involve muscle rigidity, convulsions, and loss of consciousness (tonic-clonic seizures). Additional features of pyridoxine-dependent epilepsy include low body temperature (hypothermia), poor muscle tone (dystonia) soon after birth, and irritability before a seizure episode. In rare instances, children with this condition do not have seizures until they are 1 to 3 years old. Anticonvulsant drugs, which are usually given to control seizures, are ineffective in people with pyridoxine-dependent epilepsy. Instead, people with this type of seizure are medically treated with large daily doses of pyridoxine (a type of vitamin B6 found in food). If left untreated, people with this condition can develop severe brain dysfunction (encephalopathy). Even though seizures can be controlled with pyridoxine, neurological problems such as developmental delay and learning disorders may still occur.

Pyrimidinemia familial

A metabolic error where a deficiency of an enzyme called dihydropyrimidine dehydrogenase prevents the normal metabolism of certain proteins. High levels of certain proteins are excreted in the urine. The enzyme is also needed the breakdown a chemotherapy drug called 5-flurouracil and its absence can result in a severe toxicity reaction.

Pyropoikilocytosis

A rare inherited condition where abnormal red blood cells are very sensitive to heat resulting in their destruction and hence, hemolytic anemia.

Pyrosis

Pyrosis: The occurrence of chest pain which is consistent with gastro-oesophageal reflux. See free access online books about Pyrosis below. See detailed information below for a list of 0 causes of Pyrosis, including diseases and drug side effect causes.

Pyruvate carboxylase deficiency

Pyruvate carboxylase deficiency (PCD) is a rare non-sex linked (autosomal) disorder that results from an insufficient amount of the enzyme pyruvate carboxylase. This disorder is inherited as a recessive trait and it is known to be caused by more than one different mutation in the same gene (allelic variants).

Pyruvate decarboxylase deficiency

A rare genetic disorder involving an enzyme (pyruvate decarboxylase) deficiency which results in symptoms such as failure to thrive, psychomotor retardation, small head, eye problems, increased blood ammonia levels and lactic acidosis which can result in infant death in severe cases.

Pyruvate Dehydrogenase Complex Deficiency

Pyruvate dehydrogenase complex deficiency (PDCD) is a rare disorder of carbohydrate metabolism caused by a deficiency of one of the three enzymes in the pyruvate dehydrogenase complex (PDC). The age of onset and severity of disease symptoms vary widely. Individuals with PDCD symptom onset in the prenatal period or in infancy usually die in early childhood. Those who develop PDCD later in childhood may have neurological symptoms but usually survive into adulthood. Most individuals with PDCD have an abnormality in the PDHA1 gene located on the X chromosome. A smaller percentage of affected individuals have forms of the disorder that follow autosomal recessive inheritance.

Pyruvate kinase deficiency- liver type

An inherited deficiency of pyruvate kinase which causes varying degrees of hemolytic anemia.

Pyruvate kinase deficiency- muscle type

An inherited deficiency of pyruvate kinase which causes varying degrees of hemolytic anemia.

Q fever

Q fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats and other domestic mammals, including cats and dogs. The infection results from inhalation of a spore-like small cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick borne. The incubation period is 9–40 days. Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite.

Qazi Markouizos syndrome

Qazi Markouizos syndrome (medical condition): A very rare syndrome characterized mainly by abnormal bone development and muscle problems.

Quebec platelet disorder

Quebec platelet disorder is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Quebec platelet disorder, or a subtype of Quebec platelet disorder, affects less than 200,000 people in the US population.

Quinquaud’s decalvans folliculitis

Quinquaud's decalvans folliculitis : A form of hair loss involving the gradual destruction and scarring of hair follicles which causes hair loss which spreads outwards from a central point.

Rabies

Rabies is a viral disease that causes acute inflammation of the brain in humans and other warm-blooded animals. Early symptoms can include fever and tingling at the site of exposure. These symptoms are followed by one or more of the following symptoms: violent movements, uncontrolled excitement, fear of water, an inability to move parts of the body, confusion, and loss of consciousness. Once symptoms appear it nearly always results in death. The time period between contracting the disease and the start of symptoms is usually one to three months; however, this time period can vary from less than one week to more than one year. The time is dependent on the distance the virus must travel to reach the central nervous system.

Rabson-Mendenhall syndrome

A very rare genetic disorder involving severe insulin resistance which is where the body fails to be able to use insulin which is needed to control blood sugar levels.

Radiation Maculopathy

Radiation maculopathy is a condition causing vision loss due to radiation therapy, often a delayed complication of treating <uveal melanoma or <head and neck cancers. It involves microvascular damage to the retina’s macula, leading to symptoms like macular edema, intraretinal hemorrhages, and capillary nonperfusion. While symptoms like visual distortion or blurring can occur, the most common initial finding is macular edema. Treatment primarily focuses on managing macular edema with <anti-VEGF agents and <steroids, but preventing the condition is the best strategy, and treatment outcomes are often modest or temporary.

Radio-ulnar synostosis type 1

Radioulnar synostosis type 1: A very rare syndrome characterized by fusion of the forearm bones (radius and ulna). The head of the radial bone is absent.

Radio-ulnar synostosis type 2

A very rare syndrome characterized by dislocation of the head of the radius (forearm bone) as well as fusion of the two forearm bones (radius and ulna).

Radioiodine-resistant thyroid cancer

Radioiodine-resistant (RAI-R) thyroid cancer, also known as radioiodine-refractory differentiated thyroid cancer (RAI-R DTC), occurs when thyroid cancer cells are unable to effectively uptake and utilize radioactive iodine in treatment. This resistance can lead to disease progression and potentially a poorer prognosis. RAI-R DTC is more common in older patients, those with advanced disease, and those with distant metastases.

Diseases