Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A simple enzyme-multiple auxotroph assay has been developed for the identification of newborn infants with several of the inherited metabolic defects in the Krebs cycle for the detoxification of ammonia and in the ornithine metabolic pathway. This mass screening test is used with dried filter paper blood specimens and can easily be added to existing multiple testing programs presently used in screening for phenylketonuria or congenital hypothyroidism. This assay can be used to detect patients with citrullinemia, argininosuccinic acid lyase deficiency, and argininemia. In addition to these urea cycle disorders, the several types of ornithinemia, which can result in gyrate atrophy of the retina or mental retardation, should be detectable with this assay. The strengths and weaknesses of this assay are discussed and a large-scale pilot screening trial is proposed.
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PMID:A neonatal screening test for argininosuccinic acid lyase deficiency and other urea cycle disorders. 712 51

Gyrate atrophy of the choroid and retina is characterized by autosomal recessive inheritance, progressive chorioretinal atrophy beginning in late childhood, and hyperornithinemia with ornithinuria caused by deficient ornithine aminotransferase activity. In this paper, four patients with gyrate atrophy are described. All patients had visual impairment, mental retardation, hyperornithinemia, hypolysinemia, ornithinuria and lysinuria. The first case had hypermetropic astigmatism in contrast to other reported gyrate atrophies. These are the first reported cases from Turkey, but gyrate atrophy may not be rare in Turkey since the frequency of some other metabolic disorders has also been reported to be high. It is suggested that gyrate atrophy must be considered in all patients with chorioretinal atrophy.
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PMID:Gyrate atrophy of the choroid and retina. 870 94

l-Proline concentration is primarily related to the balance of enzymatic activities of proline dehydrogenase [proline oxidase (POX)] and Delta-1-pyrroline-5-carboxylate (P5C) reductase. As a result, P5C plays a pivotal role in maintaining the concentration of proline in body fluids and inborn errors of P5C metabolism lead to disturbance of proline metabolism. Several inborn errors of proline metabolism have been described. Hyperprolinemia type I (HPI) is a result of a deficiency in POX. The POX gene (PRODH) is located on chromosome 22 (22q11.2) and this region is deleted in velo-cardio-facial syndrome, a congenital malformation syndrome. In addition, this gene locus is related to susceptibility to schizophrenia. The other type of hyperprolinemia is HPII. It is caused by a deficiency in P5C dehydrogenase activity. Hypoprolinemia, on the other hand, is found in the recently described deficiency of P5C synthetase. This enzyme defect leads to hyperammonemia associated with hypoornithinemia, hypocitrullinemia, and hypoargininemia other than hypoprolinemia. Hyperhydroxyprolinemia is an autosomal recessive inheritance disorder caused by the deficiency of hydroxyproline oxidase. There are no symptoms and it is believed to be a benign metabolic disorder. The deficiency of ornithine aminotransferase causes transient hyperammonemia during early infancy due to deficiency of ornithine in the urea cycle. In later life, gyrate atrophy of the retina occurs due to hyperornithinemia, a paradoxical phenomenon. Finally, prolidase deficiency is a rare autosomal recessive hereditary disease. Prolidase catalyzes hydrolysis of dipeptide or oligopeptide with a C-terminal proline or hydroxyproline and its deficiency can cause mental retardation and severe skin ulcers.
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PMID:Inborn errors of proline metabolism. 1880 17