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

A simple fluorescent spot screening test has been developed for the identification of individuals with arginase deficiency (hyperargininemia). The assay is based on the coversion of arginine to ornithine and urea by arginase present in 1/8 inch disc of dried blood on filter paper. The enzyme activity is visually estimated by the oxidation of NAD-H to NAD+ in a coupled kinetic reaction. In the absence of the enzyme, there is no oxidation of the NAD-H and consequently no loss of fluorescence. The screening assay has been used to identify successfully both heterozygous and homozygous arginase-deficient crabeater macaques (M. fascicularis) as well as three patients with hyperargininemia. This test can be used to screen large numbers of patients with mental retardation or seizure disorders rapidly to determine the frequency of this disorder more precisely.
 ...
PMID:A simple screening test for arginase deficiency (hyperargininemia). 84 87

A new congenital ichthyotic syndrome inherited as an autosomal recessive is described in three propositi of an Iranian family. The main clinical features are non-bullous congenital ichthyosis, mental retardation, dwarfism, and renal impairment. The nephropathy which previously has not been associated with congenital ichthyosis was manifested by raised blood urea nitrogen and creatinine levels, and a reduced creatinine clearance. The clinical and genetic features of this syndrome are discussed in relationship to the other congenital ichthyotic syndromes.
 ...
PMID:Congenital ichthyosis, mental retardation, dwarfism and renal impairment: a new syndrome. 114 23

Early diagnosis and treatment may prevent brain damage and mental retardation in young infants with inborn errors of amino acid metabolism. The abnormal blood and urinary amino acids and their metabolites are listed in two separate tables in association with each disorder to aid laboratories in making a diagnosis during screening. Because of recent developments and discoveries, more detailed descriptions and diagnostic approaches in phenylketonuria (PKU) variants and urea cycle deficiencies are also presented. The test procedures routinely used for screening inherited metabolic disorders are also described. These include five simple chemical tests to detect excessive metabolites and amino acids; a one dimensional thin layer chromatography (TLC) to screen urine for abnormal amino acid patterns; a two-dimensional TLC for semiquantitative identification of amino acids in both urine and blood; and a high performance liquid chromatographic (HPLC) method for quantitative identification of amino acids. In addition, both one- and two-dimensional chromatographies run on small thin layer cellulose plates, are introduced, modifications which save a great deal of time, labor, and reagents. A new automated HPLC system is introduced for the quantitation of both primary and secondary amino acids; the sensitivity and speed of this system is especially useful for screening large numbers of physiological fluids. It is recommended that both the urine and blood from the same patients be screened to ensure that a diagnosis is not overlooked.
 ...
PMID:Screening for inborn errors of amino acid metabolism. 202 75

Nutritional approaches are available for the management of several different classes of inborn metabolism errors. In phenylketonuria (PKU), phenylalanine is not properly metabolized; and its accumulation leads to neurologic dysfunction and metal retardation. Altering the diet to limit phenylalanine intake led to remarkable improvement in children with PKU. It was later found that instituting dietary therapy immediately after identification of the disorder in newborns prevented mental retardation. Throughout the 1960s nutritional therapies were found for other inborn disorders, including galactosemia, maple syrup urine disease, and homocystinuria. For the group of disorders associated with defects in the urea cycle, leading to profound hyperammonemia, therapy based on the concept of waste nitrogen excretion (i.e., by increasing excretion of urea cycle intermediates in the urine, nitrogen that would otherwise recycle as ammonia can be eliminated) dramatically produced better control of hyperammonemia and its consequences. Some inborn errors of metabolism respond to vitamin therapy. Biotin-related multiple carboxylase synthetase deficiency can be produced by either of two enzyme defects--holocarboxylase synthetase deficiency or biotinidase deficiency. Both are treatable with biotin supplementation. The symptoms of multiple carboxylase deficiency can also occur after intestinal resection or ingestion of raw eggs. Multiple carboxylase deficiency has been treated successfully in utero by giving the mother biotin supplements. Peroxisomal disorders may respond to dietary management. Liver disease in hereditary tyrosinemia may be accentuated by hypermethioninemia and treated by controlling the blood methionine level. Glycogen storage disease Type I, which causes hypoglycemia, can be controlled by oral administration of cornstarch.
 ...
PMID:Nutritional therapy for selected inborn errors of metabolism. 268 28

Pregnant rats were loaded with L-phenylalanine, and the distributions of [14C]leucine and [14C]urea into fetal plasma and tissues were examined. Uptake of [14C]leucine into the supernatant and protein fractions of fetal plasma and tissues was low in the rats loaded with phenylalanine. In contrast, [14C]urea was distributed identically in both groups, indicating that maternal hyperphenylalaninemia did not affect blood flow across the placenta. Administration of phenylalanine and p-chlorophenylalanine produced amino acid imbalance in fetal tissues. Along with these changes, polysomes of the affected fetal heart and brain disaggregated without changes in the ribonuclease activity. These results indicate that high phenylalanine levels in maternal plasma disturb the active transport of amino acids across the placenta, causing an amino acid imbalance and disaggregation of polysomes in fetal heart and brain. These changes may contribute to the congenital heart disease and mental retardation of maternal phenylketonuria.
 ...
PMID:Effects of phenylalanine loading on protein synthesis in the fetal heart and brain of rat: an experimental approach to maternal phenylketonuria. 294 18

Two siblings with hyperornithinemia, hyperammonemia, and homocitrullinuria are reported. The clinical picture included protein intolerance, mental retardation, seizures, and stuporous episodes. One patient had cerebellar ataxia, myoclonus, convulsive seizure, and muscular weakness in both legs. Isolated liver mitochondria in the patient revealed that ornithine transport and citrulline synthesis were decreased, but urea cycle enzymes and ornithine aminotransferase were normal. Ornithine metabolism was decreased in cultured skin fibroblasts.
 ...
PMID:Hyperornithinemia, hyperammonemia, and homocitrullinuria: case report and biochemical study. 367 Jun 19

Two cases of citrullinemia were reported. Case 1 was an one month old female. Her clinical course and findings were different from the fulminant type of neonatal citrullinemia reported in predominantly Caucasian countries. Our patient was well controlled under a low protein diet and essential amino acids till 9 months of age, but unfortunately she died of Reye's like syndrome. Case 2 was 31 year old male (at the time of death). He was admitted to our hospital because of hyperammonemia and mental retardation. By subsequent laboratory investigations he was diagnosed as having adult type of citrullinemia and died of hepatoma. Enzymological analysis revealed that argininosuccinate synthetase (ASS) activities in the liver tissues of the patients decreased to 40% (Case 1), 20% (Case 2) compared with those in control liver tissues. The other urea cycle enzyme activities were all within normal range. ASS activities in the kidney and brains of the two cases were within normal range. The kinetic constant values of ASS for three substrates in the tissues of liver and kidney were all normal. Results of immunochemical analyses indicated that citrullinemia in our patients was caused by a quantitative deficiency of ASS associated proteins of the liver and kidney tissues as to the molecular weight.
 ...
PMID:Citrullinemia: quantitative deficiency of argininosuccinate synthetase in the liver. 373 4

Two sisters with similar clinical features are described. Their clinical manifestations include mental retardation, delayed speech development, low percentiles for height, weight and head circumference, dysmorphic ears, cubitus valgus, pseudoclubbing of fingers, flexion deformity of toes, small kidneys, elevated serum creatinine and blood urea nitrogen (BUN). High resolution chromosome analysis revealed a complete deletion of 16qh with a concurrent small deletion of the adjacent euchromatic segment 16q12.1 in one of the no. 16 chromosomes of both sisters, whereas the parents had normal no. 16 chromosomes. Length polymorphism of the 16qh regions appeared to indicate a maternal origin of the deleted no. 16 chromosome in both sisters. The clinical features of both sisters were attributed to the 16q12.1 deletion. Since both parents were cytogenetically normal, the two sisters were considered as a recurrence of a similar de novo interstitial deletion. Possible mechanisms which could lead to recurrence of a seemingly de novo event are discussed.
 ...
PMID:Recurrent de novo interstitial deletion of 16q in two mentally retarded sisters. 399 93

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.
 ...
PMID:A neonatal screening test for argininosuccinic acid lyase deficiency and other urea cycle disorders. 712 51

Argininosuccinic aciduria (ASA-uria) is a rare inborn error of the urea cycle, in which there is massive excretion of argininosuccinic acid (ASA) in the urine together with elevated concentrations of ASA in the plasma and the CSF. The characteristic symptoms are either those of overwhelming metabolic disease in the newborn period, or variable psychomotor retardation. The present patient, the first Finnish one to be reported, was a 49-year-old woman. She was hospitalized at the age of 26 with a diagnosis schizophrenia and mental retardation. Her clinical symptoms consisted of ataxia, disturbance of coordination, clumsiness, intention treMor and a positive Romberg's sign. The laboratory findings were consistent with the mild, late-onset type of ASA-uria.
 ...
PMID:Argininosuccinic aciduria in a Finnish woman presenting with psychosis and mental retardation. 713 86


1 2 3 4 5 Next >>