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)

Governmental officials as well as medical scientists in Taiwan have worked hard in recent years to develop and to implement various measures, such as prenatal diagnosis and neonatal screening, to lower the incidence of hereditary diseases and mental retardation in the population. An inquiry into the possibility of devising a chromosomal and biochemical screening program and to apply it routinely to all the mentally retarded school children island-wide was the major aim of the present study. A collection of 1,614 blood samples was screened for phenylketonuria (PKU), galactosemia, homocystinuria, biotinidase deficiency, and congenital hypothyroidism. The IQ of these children ranged from 50-75 (1,397 children, moderate group) to less than 50 (217 children, severe group). Six cases of PKU (one tetrahydrobiopterin deficient and five classical) and three cases of thyroid dysfunction were found. The overall incidence of these two diseases was 0.56%. Of the 1,614 blood samples, 1,323 were cultured and karyotyped successfully. One hundred and twenty-five of them had chromosome abnormalities. The majority (64 out of 125) were trisomy 21. A remarkable difference in the percentage of mentally retarded children with chromosome abnormalities was observed between the moderate (7.87%) and severe (17.51%) retarded.
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PMID:Chromosomal and biochemical screening on mentally retarded school children in Taiwan. 175 40

Coffin-Siris syndrome is an infrequent condition characterised by mental retardation, nail hypoplasia or absence with fifth digit involvement and feeding problems. In addition, sparse scalp hair and chronic intractable eczema has been described in this syndrome. We report a 26-month-old girl with the disease and partial biotinidase deficiency.
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PMID:Partial biotinidase deficiency associated with Coffin-Siris syndrome. 191 29

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.
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PMID:Nutritional therapy for selected inborn errors of metabolism. 268 28

Ten patients with biotinidase deficiency were studied. Clinical findings at presentation varied with dermatological signs (dermatitis and alopecia), neurological abnormalities (fits, hypotonia, and ataxia), and recurrent infections being the most common features, although none of these occurred in every case. Biochemically the disease is characterised by metabolic acidosis and organic aciduria. Treatment with biotin results in pronounced, rapid, clinical and biochemical improvement, but some patients have residual neurological damage comprising neurosensory hearing loss, visual pathway defects, ataxia, and mental retardation. The cause of this permanent damage remains obscure and it is not clear if the early introduction of treatment will prevent it.
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PMID:Biotinidase deficiency: a survey of 10 cases. 319 50

A group of 28 patients with inherited metabolic disease (homocystinuria galactosaemia, maple syrup urine disease and biotinidase deficiency) diagnosed by screening were compared with a group of 17 similar patients identified clinically. The rate of hospitalization was similar for the two groups. The patients diagnosed clinically showed a higher incidence of mental retardation and their parents experienced greater stress and found greater difficulty in meeting their child's needs.
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PMID:Newborn screening compared to clinical identification of biochemical genetic disorders. 1263 45

Biotin is a water-soluble vitamin that serves as an essential coenzyme for five carboxylases in mammals. Biotin-dependent carboxylases catalyze the fixation of bicarbonate in organic acids and play crucial roles in the metabolism of fatty acids, amino acids and glucose. Carboxylase activities decrease substantially in response to biotin deficiency. Biotin is also covalently attached to histones; biotinylated histones are enriched in repeat regions in the human genome and appear to play a role in transcriptional repression of genes and genome stability. Biotin deficiency may be caused by insufficient dietary uptake of biotin, drug-vitamin interactions and, perhaps, by increased biotin catabolism during pregnancy and in smokers. Biotin deficiency can also be precipitated by decreased activities of the following proteins that play critical roles in biotin homeostasis: the vitamin transporters sodium-dependent multivitamin transporter and monocarboxylate transporter 1, which mediate biotin transport in the intestine, liver and peripheral tissues, and renal reabsorption; holocarboxylase synthetase, which mediates the binding of biotin to carboxylases and histones; and biotinidase, which plays a central role in the intestinal absorption of biotin, the transport of biotin in plasma and the regulation of histone biotinylation. Symptoms of biotin deficiency include seizures, hypotonia, ataxia, dermatitis, hair loss, mental retardation, ketolactic acidosis, organic aciduria and also fetal malformations. This review focuses on the deficiencies of both biotin and biotinidase, and the medical management of such cases.
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PMID:Biotin and biotinidase deficiency. 1972 38

Patients with severe biotinidase deficiency (BD), if untreated, may exhibit seizures, psychomotor delay, deafness, ataxia, visual pathology, conjunctivitis, alopecia, and dermatitis. Clinical features normally appear within the first months of life, between two and five. Seizures are one of the most common symptoms in these patients (55%), usually presented as generalized tonic-clonic, and improving within 24 h of biotin treatment. Treatment delay has been associated with irreversible neurological damage, mental retardation, ataxia, paraparesis, deafness, and epilepsy exceptionally.We report the case of a girl who was admitted at 2.5 months because of vomiting, failure to thrive, flexor spasms, dermatitis, and neurological depression for 1 month. BD was identified and was treated with biotin, stopping seizures and improving symptoms. Developmental delay, paraparesis, optic atrophy, and seizures during febrile illness were observed at follow-up. At the age of 8, she suffered hemigeneralized seizures despite appropriate biotin treatment, so levetiracetam was administered, and epilepsy was controlled. Organic acid measurement was performed to determine whether the child was receiving enough or no biotin.Even though BD is a rare condition, because the biotinidase screening is a reliable procedure and the disorder is readily treatable, the implementation of extended biotinidase screening will effectively help to prevent any acute and long-term neurological problems as well as the significant morbidity associated with untreated disease. In addition, neonatal screening and early treatment with biotin prevents severe neurological sequelae, such as epilepsy, which has not been thoroughly described in the literature.
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PMID:Epilepsy in biotinidase deficiency after biotin treatment. 2343 Aug 99

Inborn error of metabolism may produce a complex clinical picture in which epilepsy is only one of the various neurologic manifestations including developmental delay/regression, mental retardation, and movement disorders. However, metabolic epilepsies may dominate the clinical presentation. A specific diagnosis of metabolic disorders in epileptic patients may provide the possibility of specific treatments that can improve seizures. In a few metabolic diseases such as vitamin-responsive epilepsies, epilepsy responds to specific treatments based on supplementation of cofactors. Certain rare vitamin-responsive inborn errors of metabolism may present as early encephalopathy with anticonvulsant-resistant seizures. These include pyridoxine-dependent seizures, pyridoxal-phosphate-dependent seizures, folinic acid-responsive seizures, and biotinidase deficiency. This review discusses our current understanding of these vitamin-responsive epilepsies.
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PMID:[Vitamin-responsive epilepsies: an update]. 2408 39