Phenylketonurias: A group of autosomal recessive disorders marked by a deficiency of the hepatic enzyme PHENYLALANINE HYDROXYLASE or less frequently by reduced activity of DIHYDROPTERIDINE REDUCTASE (i.e., atypical phenylketonuria). Classical phenylketonuria is caused by a severe deficiency of phenylalanine hydroxylase and presents in infancy with developmental delay; SEIZURES; skin HYPOPIGMENTATION; ECZEMA; and demyelination in the central nervous system. (From Adams et al., Principles of Neurology, 6th ed, p952).Phenylketonuria, Maternal: A condition occurring in untreated or partially treated females with PHENYLKETONURIA when they become pregnant. This may result in damages to the FETUS, including MICROCEPHALY; MENTAL RETARDATION; congenital heart disease; FETAL GROWTH RETARDATION; and CRANIOFACIAL ABNORMALITIES. (From Am J Med Genet 1997 Mar 3;69(1):89-95)Phenylalanine Hydroxylase: An enzyme of the oxidoreductase class that catalyzes the formation of L-TYROSINE, dihydrobiopterin, and water from L-PHENYLALANINE, tetrahydrobiopterin, and oxygen. Deficiency of this enzyme may cause PHENYLKETONURIAS and PHENYLKETONURIA, MATERNAL. EC 1.14.16.1.Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.Phenylpyruvic Acids: A group of compounds that are derivatives of phenylpyruvic acid which has the general formula C6H5CH2COCOOH, and is a metabolite of phenylalanine. (From Dorland, 28th ed)Biopterin: A natural product that has been considered as a growth factor for some insects.Neonatal Screening: The identification of selected parameters in newborn infants by various tests, examinations, or other procedures. Screening may be performed by clinical or laboratory measures. A screening test is designed to sort out healthy neonates (INFANT, NEWBORN) from those not well, but the screening test is not intended as a diagnostic device, rather instead as epidemiologic.Anabaena variabilis: A species of ANABAENA that can form SPORES called akinetes.Metabolism, Inborn Errors: Errors in metabolic processes resulting from inborn genetic mutations that are inherited or acquired in utero.Microcephaly: A congenital abnormality in which the CEREBRUM is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (Desk Reference for Neuroscience, 2nd ed.)Infant, Newborn: An infant during the first month after birth.Diet Therapy: By adjusting the quantity and quality of food intake to improve health status of an individual. This term does not include the methods of food intake (NUTRITIONAL SUPPORT).Intelligence: The ability to learn and to deal with new situations and to deal effectively with tasks involving abstractions.Phenylalanine Ammonia-Lyase: An enzyme that catalyzes the deamination of PHENYLALANINE to form trans-cinnamate and ammonia.Homogentisic AcidCongenital Hypothyroidism: A condition in infancy or early childhood due to an in-utero deficiency of THYROID HORMONES that can be caused by genetic or environmental factors, such as thyroid dysgenesis or HYPOTHYROIDISM in infants of mothers treated with THIOURACIL during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe MENTAL RETARDATION, impaired skeletal development, short stature, and MYXEDEMA.Intellectual Disability: Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual has an intellectual disability. IQ scores between 70 and 79 are in the borderline range. Scores below 67 are in the disabled range. (from Joynt, Clinical Neurology, 1992, Ch55, p28)Diet, Protein-Restricted: A diet that contains limited amounts of protein. It is prescribed in some cases to slow the progression of renal failure. (From Segen, Dictionary of Modern Medicine, 1992)Galactosemias: A group of inherited enzyme deficiencies which feature elevations of GALACTOSE in the blood. This condition may be associated with deficiencies of GALACTOKINASE; UDPGLUCOSE-HEXOSE-1-PHOSPHATE URIDYLYLTRANSFERASE; or UDPGLUCOSE 4-EPIMERASE. The classic form is caused by UDPglucose-Hexose-1-Phosphate Uridylyltransferase deficiency, and presents in infancy with FAILURE TO THRIVE; VOMITING; and INTRACRANIAL HYPERTENSION. Affected individuals also may develop MENTAL RETARDATION; JAUNDICE; hepatosplenomegaly; ovarian failure (PRIMARY OVARIAN INSUFFICIENCY); and cataracts. (From Menkes, Textbook of Child Neurology, 5th ed, pp61-3)Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.No-Observed-Adverse-Effect Level: The highest dosage administered that does not produce toxic effects.Body Fluids: Liquid components of living organisms.Russia (Pre-1917)Food, Formulated: Food and dietary formulations including elemental (chemically defined formula) diets, synthetic and semisynthetic diets, space diets, weight-reduction formulas, tube-feeding diets, complete liquid diets, and supplemental liquid and solid diets.MassachusettsAspartame: Flavoring agent sweeter than sugar, metabolized as PHENYLALANINE and ASPARTIC ACID.Sweetening Agents: Substances that sweeten food, beverages, medications, etc., such as sugar, saccharine or other low-calorie synthetic products. (From Random House Unabridged Dictionary, 2d ed)MarylandAmino Acids, Essential: Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Hospitals, Voluntary: Private, not-for-profit hospitals that are autonomous, self-established, and self-supported.Health Promotion: Encouraging consumer behaviors most likely to optimize health potentials (physical and psychosocial) through health information, preventive programs, and access to medical care.BostonHospitals, Pediatric: Special hospitals which provide care for ill children.Focal InfectionMaineMultimedia: Materials, frequently computer applications, that combine some or all of text, sound, graphics, animation, and video into integrated packages. (Thesaurus of ERIC Descriptors, 1994)Genes, Recessive: Genes that influence the PHENOTYPE only in the homozygous state.Orphan Drug Production: Production of drugs or biologicals which are unlikely to be manufactured by private industry unless special incentives are provided by others.Rare Diseases: A large group of diseases which are characterized by a low prevalence in the population. They frequently are associated with problems in diagnosis and treatment.Drug Delivery Systems: Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.SwitzerlandFenclonine: A selective and irreversible inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin (5-HYDROXYTRYPTAMINE). Fenclonine acts pharmacologically to deplete endogenous levels of serotonin.Consensus Development Conferences, NIH as Topic: Articles on conferences sponsored by NIH presenting summary statements representing the majority agreement of physicians, scientists, and other professionals convening for the purpose of reaching a consensus on a subject of interest. This heading is used for NIH consensus conferences as a means of scientific communication. In indexing it is viewed as a type of review article and as a tag for any article appearing in any publication of the NIH Office of Medical Applications of Research (OMAR).Consensus Development ConferenceConsensus Development Conference, NIHDecision Making: The process of making a selective intellectual judgment when presented with several complex alternatives consisting of several variables, and usually defining a course of action or an idea.Consensus Development Conferences as Topic: Presentations of summary statements representing the majority agreement of physicians, scientists, and other professionals convening for the purpose of reaching a consensus--often with findings and recommendations--on a subject of interest. The Conference, consisting of participants representing the scientific and lay viewpoints, is a significant means of evaluating current medical thought and reflects the latest advances in research for the respective field being addressed.Diabetic Ketoacidosis: A life-threatening complication of diabetes mellitus, primarily of TYPE 1 DIABETES MELLITUS with severe INSULIN deficiency and extreme HYPERGLYCEMIA. It is characterized by KETOSIS; DEHYDRATION; and depressed consciousness leading to COMA.KentuckyTremor: Cyclical movement of a body part that can represent either a physiologic process or a manifestation of disease. Intention or action tremor, a common manifestation of CEREBELLAR DISEASES, is aggravated by movement. In contrast, resting tremor is maximal when there is no attempt at voluntary movement, and occurs as a relatively frequent manifestation of PARKINSON DISEASE.