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)

The CNS infection by HIV-1 in infancy could be present immediately after infection or became manifest later. Microcephalia, mental retardation, pyramidal signs, humor and behavioral disorders and antiretroviral therapy complications are common. This is an observational, sectional and descriptive study about findings on neurological examination of 173 patients in a group of children and adolescents infected and exposed to HIV-1 in perinatal period. Most of them had more than one neurological finding or different diagnosis. The more common findings were: encephalopathy, mental retardation, language delay, pyramidal signs, hyporeflexia. The neurological examination was abnormal in 67% of all patients even in seroreverters. We suggest that this group has a high risk to neurological disease and the development of co-morbidity is directly correlated to clinical deterioration by HIV-1 infection.
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PMID:[Neurological findings in a group of children and adolescents exposed and infected by HIV-1]. 1625 64

Inherited disorders of neurotransmitters are a group of neurometabolic syndromes attributable to a primary disturbance of neurotransmitter metabolism or transport. This is an enlarging group of recognized disorders requiring specialized diagnostic procedures for detection. This review considers clinical disorders of biopterin, catecholamines, serotonin, glycine, pyridoxine, and GABA metabolism. Newly described syndromes such as cerebral folate deficiency and pyridoxal-5-phosphate dependency are included. The disorders of the metabolic pathways of biopterin, catecholamines, and serotonin are linked due to their common synthetic components. Glycine encephalopathy represents an enlarging phenotype related to abnormalities of the glycine degradative cleavage system. Both pyridoxine and pyridoxal-5-phosphate dependency need to be considered in refractory neonatal seizures. The most common disorder of GABA metabolism is SSADH deficiency, which has a broad phenotype of mental retardation, epilepsy, ataxia, and hyporeflexia and which invokes the combined problems of elevated brain GABA and GHB.
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PMID:Inherited disorders of neurotransmitters in children and adults. 1629 54

The COACH syndrome is a very rare disorder with cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, and hepatic fibrosis. Nineteen cases with COACH diagnosis have been reported. Neurologic abnormalities are the first symptoms in most cases. Complications of the hepatopathy [portal hypertension, esophageal varices, and gastrointestinal (GI) bleeding] contribute extensively to the morbidity and lethality in the course of the disease. We describe a 28-yr-old female with COACH syndrome resulting in chronic renal and hepatic insufficiency. The patient was found to have significant mental retardation, truncal ataxia, motor abnormality and occulomotor abnormality. She began to develop GI bleeding and encephalopathy because of biopsy-confirmed cirrhosis. We performed combined liver and kidney transplant after challenging discussion. Her postoperative course was uneventful, and she was discharged on the ninth postoperative day (POD). She has not had any problems at 1, 3 and 5-yr follow-up with excellent liver and renal function. This is the first description of successful combined liver and kidney transplant with long-term follow-up. The decision for transplant is challenging because COACH syndrome is rare with only descriptive characterization and patients have non-progressive ataxia and mental retardation. However, our case shows that liver and kidney transplant can be medically successful, and the individuals achieve long-term success if they have a stable neurological condition and an excellent support system.
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PMID:Successful combined liver and kidney transplant for COACH syndrome and 5-yr follow-up. 1631 15

The authors report the clinical, neuroimaging, muscle biopsy and mtDNA findings in a patient affected by bilateral hearing loss and mental retardation since infancy, presenting at age 31 years with a rapid deterioration of mental status and ataxia leading to vegetative condition and death at the age of 32 years. Clinical and genetic studies have been also performed in the mother, affected by neurosensorial hearing loss. Muscle biopsy showed severe mitochondrial alterations in the propositus and evidence of mitochondrial alterations in his mother. Direct mtDNA sequencing in all family members revealed the known 7472insC mutation and the recently described A7472C sequence variation in the tRNA(Ser(UCN))gene. RFLP-PCR confirmed the heteroplasmic nature of the two mutations and failed to find the second transversion in 200 controls. The percentage of mutant genomes harbouring 7472insC ranged from 3 to 7% in asymptomatic family members to 70% in the proband and his mother, whereas the percentage of A7472C mutant genomes was about 90% in all maternal relatives except the proband (56%) and his sister (5%). In conclusion, this is the first report of a rapidly progressive encephalopathy in association with the 7472insC mutation in mtDNA, combined with an A>C variation at the same nucleotide with a possible suppression effect on the pathogenic mutation.
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PMID:Rapidly progressive neurodegeneration in a case with the 7472insC mutation and the A7472C polymorphism in the mtDNA tRNA ser(UCN) gene. 1636 37

Mutations in the methyl-CpG-binding protein 2 (MECP2) gene located on Xq28, cause Rett syndrome (RTT) in female patients. Meanwhile, nonmosaic MECP2 mutations unknown in girls have been found in an increasing number of male patients with a normal 46, XY karyotype. They can cause a broad spectrum of neurodevelopmental disorders which often show a combination of mental retardation (MR) with neurological symptoms. We present the results of MECP2 analysis in a group of 72 male patients with an unexplained combination of MR and neurological features, and review the mutational reports published on male patients since the discovery of the MECP2 gene. Analysis included sequencing of exon 1 which thus far was mostly omitted from DNA screening. One pathogenic mutation has been found in a patient with Rett variant, in addition to an unclassified variant and a series of nonpathogenic changes. No changes have been found in exon 1. Criteria for testing of male patients are classic RTT, severe neonatal encephalopathy, and RTT variant which may be clinically underrecognized. Testing can also be considered in males with a combination of unexplained MR and (progressive) neurological manifestations although the yield of MECP2 analysis is probably low in this situation. Based on the literature, MECP2 testing in males with MR only is debatable.
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PMID:MECP2 mutations are an infrequent cause of mental retardation associated with neurological problems in male patients. 1637 10

Brooks, Wisniewski, and Brown described a familial presentation of severe developmental retardation, speech delay, static encephalopathy with atrophic hydrocephalus, microcephaly, progressive spastic diplegia, a characteristic facial appearance, optic atrophy, and growth retardation associated with hypoplastic corpus callosum in one of the patients. The authors postulated a distinct X-linked mental retardation syndrome. Later on a similar phenotype was observed in three male siblings with an early lethal outcome. Here we describe three patients with several overlapping features and a progressive neurological picture presenting with a significantly compromised mitochondrial oxidative phosphorylation measured in a fresh muscle biopsy. Neurological deterioration is a commonly observed feature in mitochondrial disorders. Based on the unique combination of the clinical symptoms, we suggest that our patients have the Brooks-Wisniewski-Brown syndrome.
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PMID:Mitochondrial dysfunction in Brooks-Wisniewski-Brown syndrome. 1647 54

Rett syndrome, a neurodevelopmental disorder caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2), is a leading cause of mental retardation with autistic features in females. MECP2 mutations have also been identified in individuals with a variety of clinical syndromes, including mild learning-disability in females, neonatal encephalopathy in males, and psychiatric disorders, autism and X-linked mental retardation in both males and females. Furthermore, MECP2 duplications have been shown to cause a progressive postnatal neurological disorder. MeCP2 is a transcriptional repressor that binds to methylated CpG dinucleotides flanked by AT-rich segments and recruits a co-repressor complex, thereby altering chromatin structure. Subtle gene expression changes have been identified in Rett patients and mouse models; however, MeCP2 dysfunction has also been shown to cause abnormalities of RNA splicing, suggesting a complex molecular pathogenesis. Discovering which genes are misregulated in the absence of functional MeCP2 and demonstrating their role in causing neuronal dysfunction and disease manifestations are challenging but important steps for understanding the pathogenesis of Rett syndrome and related disorders.
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PMID:MeCP2 dysfunction in Rett syndrome and related disorders. 1664 48

Rett syndrome (RTT) is an X-linked progressive encephalopathy. Mutations in the MECP2 (methyl-CpG-binding protein) gene have been found to cause RTT. In the past few years, the role of MECP2 mutations in patients with mental disorders other than RTT has been studied, finding that mutations in MECP2 also contribute to non-syndromic entities. More recently, it has been demonstrated that RTT shares clinical features with those of Angelman syndrome, another neurodevelopmental disorder. These observations must be confirmed in a large series, to better understand the criteria needed for justifying a molecular test. Consequently, we have searched for MECP2 mutations in 294 patients (43 Angelman and Prader-Willi like included) with mental retardation (MR) of unknown aetiology. We found six polymorphisms (three novel, three previously reported) in 10 patients, one novel unclassified silent change (p.V222V) in a man, and one causative mutation in a girl with MR. Once this case was clinically reviewed, the girl presented symptoms of atypical RTT. The mutation (p.Y141C) lies within the methyl-binding domain, and has only been reported once in another atypical RTT. Our results show that the MECP2 mutations account for a low frequency (1/416 chromosomes = 0.24%) among mentally retarded individuals, which imply that it is necessary to perform an exhaustive clinical examination of patients before determining whether analysis of MECP2 is required or not.
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PMID:Screening for MECP2 mutations in Spanish patients with an unexplained mental retardation. 1687 96

Nonketotic hyperglycinemia is a disorder of amino acid metabolism in which a defect in the glycine cleavage system leads to an accumulation of glycine in the brain and other body compartments. In the classical form it presents as neonatal apnea, intractable seizures, and hypotonia, followed by significant psychomotor retardation. An important subset of children with nonketotic hyperglycinemia are atypical variants who present in a heterogeneous manner. This report describes a patient with mild language delay and mental retardation, who was found to have nonketotic hyperglycinemia following her presentation with acute encephalopathy and chorea shortly after initiation of valproate therapy.
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PMID:Valproate-induced chorea and encephalopathy in atypical nonketotic hyperglycinemia. 1762 31

Severe Myoclonic Epilepsy in infancy (SMEI, or Dravet syndrome) is a drug-resistant epilepsy that occurs in the first year of life of previously healthy children. The main clinical features are prolonged and repeated febrile and afebrile generalized or unilateral convulsive seizures. In the course of the epilepsy, cognitive deterioration becomes evident, and interictal myoclonus, clumsiness and ataxia appear. One third of the children with SMEI show de novo mutations of the SCN1A gene, and additional familial genes probably contribute to the phenotype. While the clinical picture of SMEI has been well studied, neuropsychological data remain scarce. Global mental retardation, attention deficit and psychotic behavior have been reported but the long-term outcome has not been evaluated. We conducted a longitudinal neuropsychological study of children with SMEI. Twenty children, aged 11 months to 16 years, were prospectively examined using standardized neuropsychological tests. Correlation analysis with other clinical features was performed in 12 cases. Marked slowing or stagnation of psychomotor development, accompanied by psychotic or autistic traits and hyperactivity, was observed between the ages of one and four years. In the later stages (at ages 5 to 16 years), cognitive function stabilized but remained below normal. In children with a more favorable course, language capacities were better preserved than visuospatial functions, and behavior improved. The cognitive and behavioral impairment tended to correlate with the frequency of convulsive seizures (>5 per month). The data suggest that SMEI can be considered as a prototype of an epileptic encephalopathy.
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PMID:Severe myoclonic epilepsy of infants (Dravet syndrome): natural history and neuropsychological findings. 1710 60


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