Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Cerebral palsy (CP) is defined as any nonprogressive motor deficits resulting from cerebral abnormalities that occur in the prenatal or perinatal period. Symptoms become apparent during the first year of life. Genetic forms of CP account for about 2% in European populations but are thought to cause a substantial proportion in consanguineous families. We have identified a large consanguineous family from Oman with spastic diplegia, microcephaly, and mental retardation. Additional manifestations include hyperreflexia, clumsiness, unstable gait, drooling, and dysarthria. There was phenotypic variability among different individuals, but spastic diplegia, microcephaly, and mental retardation were three constant traits present in all affected individuals.
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PMID:An autosomal recessive form of spastic cerebral palsy (CP) with microcephaly and mental retardation. 1676 Dec 94

Intractable epilepsy and peculiar EEG patterns characterize ring chromosome 20 syndrome [r(20)], while dysmorphic features, mental retardation and behavioural disturbances are widely variable. The clinical evolution of r(20) over time is not well defined as relatively few cases have been reported. Here we describe a patient with severe clinical features followed for a 25-year period. The patient was subjected to clinical, psychometric and EEG evaluation twice a year from the age of 21 years. Cytogenetic studies, using chromosome analysis and fluorescence in situ hybridization (FISH) and several immunological investigations were performed. Ring chromosome 20 was found in 50% of examined metaphases with the deletion of subtelomeric regions 20p and 20q. Our patient presented with marked dysmorphic features, severe mental retardation, tetraparesis, dysarthria and intractable epilepsy with onset during the first year of life. During follow up, EEG findings and clinical features progressively worsened: a progressive disorganization of background EEG activity occurred and mental and motor impairment evolved. The severity of clinical expression depended on the extent of chromosomal deletion and on the haploinsufficiency of other important related genetic loci due to ring instability. The progressive worsening of both clinical and EEG features over a long period, which has also been reported by other authors, further characterized this syndrome.
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PMID:Electroclinical evolution in ring chromosome 20 epilepsy syndrome: a case with severe phenotypic features followed for 25 years. 1680 95

Childhood ataxias are a complex set of inherited disorders. Ataxias associated with generalized tonic-clonic epilepsy are usually included with the progressive myoclonus epilepsies (PME). Five disease entities, Unverricht-Lundborg disease, Lafora's disease, neuronal ceroid lipofuscinoses, myoclonic epilepsy with ragged red fibres and sialidoses, account for the majority of PME cases. Two rare forms of ataxia plus epilepsy, sensory ataxic neuropathy, dysarthria and ophthalmoparesis, and infantile onset spinocerebellar ataxia were described recently and found to be caused by defective mitochondrial proteins. We report here a large consanguineous family from Saudi Arabia with four affected children presenting with generalized tonic-clonic epilepsy, ataxia and mental retardation, but neither myoclonus nor mental deterioration. MRI and muscle biopsy of one patient revealed, respectively, posterior white matter hyperintensities and vacuolization of the sarcotubular system. We localized the defective gene by homozygosity mapping to a 19 Mb interval in 16q21-q23 between markers D16S3091 and D16S3050. Linkage studies in this region will allow testing for homogeneity of this novel ataxia-epilepsy entity.
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PMID:A new form of childhood onset, autosomal recessive spinocerebellar ataxia and epilepsy is localized at 16q21-q23. 1747 Apr 96

We assessed intelligence and receptive and expressive language skills in 6 children, ages 7 years 9 months to 12 years 4 months, with bilateral perisylvian polymicrogyria of variable extent and with dysarthria of different severity. In view of the recent findings of a close relationship between word and gesture, we also examined the communicative use of gesture. We found that mental retardation was related to the extent of cortical malformation; lexical comprehension, but not morphosyntactic comprehension, and verbal production were more compromised than expected from nonverbal intellectual abilities; lack of verbal language was not compensated by the use of referential gestures. Results are discussed suggesting that compromised verbal and gestural communication in bilateral perisylvian polymicrogyria are not due simply to mental retardation and/or dysarthria but also to dysfunction of Sylvian fissure areas concerned with the totality of language processing.
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PMID:Verbal and gestural communication in children with bilateral perisylvian polymicrogyria. 1789 Apr 6

Woodhouse Sakati syndrome is a rare autosomal recessive neuroendocrine disorder characterized by the combination of alopecia, hypogonadism, diabetes mellitus, mental retardation, sensory neural deafness and extrapyramidal features. Movement disorders mainly consist of dystonia and chorea of the limbs with onset in adolescence. Facial muscles are usually spared, but dysarthria is common. Pyramidal features and peripheral abnormalities are inconsistent features. Most of the reported families are from the Middle Eastern countries although rarely Caucasian cases have been described. Here we present clinical details of two affected siblings from a new Middle East family and draw attention of movement disorder specialists to this entity. We summarize findings from pervious cases with particular focus on neurological and movement disorder features.
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PMID:Dystonia in the Woodhouse Sakati syndrome: A new family and literature review. 1817 54

Angelman syndrome (AS) is a childhood-onset neurogenetic disorder characterized by functionally severe developmental delay with mental retardation, deficits in expressive language, ataxia, appendicular action tremors and unique behaviors such as inappropriate laughter and stimulus-sensitive hyperexcitibility. Most cases of AS are caused by mutations which disrupt expression of maternal UBE3A. Although some progress has been made in understanding hippocampal-related memory and learning aspects of the disorder using Ube3a deficient mice, the numerous motoric abnormalities associated with AS (ataxia, action tremor, dysarthria, dysphagia, sialorrhea and excessive chewing/mouthing behaviors) have not been fully explored with mouse models. Here we use a novel quantifiable analysis of fluid consumption and licking behavior along with a battery of motor tests to examine cerebellar and other motor system defects in Ube3a deficient mice. Mice with a maternally inherited Ube3a deficiency (Ube3a(m-/p+)) show defects in fluid consumption behavior which are different from Ube3a(m-/p-) mice. The rhythm of fluid licking and number of licks per visit were significantly different among the three groups (m-/p-, m-/p+, m+/p+) and indicate that not only was fluid consumption dependent on Ube3a expression in the cerebellum, but may also depend on low levels of Ube3a expression in other brain regions. Additional neurological testing revealed defects in both Ube3a(m-/p+) and Ube3a(m-/p-) mice in rope climbing, grip strength, gait and a raised-beam task. Long-term observation of fluid consumption behavior is the first phenotype reported that differentiates between mice with a maternal loss of function versus complete loss of Ube3a in the brain. The neuronal and molecular mechanisms underlying mouse fluid consumption defects specifically associated with maternally inherited Ube3a deficiency may reveal important new insights into the pathobiology of AS in humans.
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PMID:Analysis of cerebellar function in Ube3a-deficient mice reveals novel genotype-specific behaviors. 1841 22

Impaired glucose transport across the blood brain barrier results in glucose transporter type 1 (GLUT-1) deficiency syndrome, first described in 1991. It is characterized by infantile seizures refractory to anticonvulsive treatments, microcephaly, delays in mental and motor development, spasticity, ataxia, dysarthria and other paroxysmal neurologic phenomena, often occurring prior to meals. Affected infants are normal at birth following an uneventful pregnancy and delivery. Seizures usually begin between the age of one and four months and can be preceded by apneic episodes or abnormal eyes movements. Patients with atypical presentations such as mental retardation and intermittent ataxia without seizures, or movement disorders characterized by choreoathetosis and dystonia, have also been described. Glucose is the principal fuel source for the brain and GLUT-1 is the only vehicle by which glucose enters the brain. In case of GLUT-1 deficiency, the risk of clinical manifestations is increased in infancy and childhood, when the brain glucose demand is maximal. The hallmark of the disease is a low glucose concentration in the cerebrospinal fluid in a presence of normoglycemia (cerebrospinal fluid/blood glucose ratio less than 0.4). The GLUT-1 defect can be confirmed by molecular analysis of the SCL2A1 gene or in erythrocytes by glucose uptake studies and GLUT-1 immunoreactivity. Several heterozygous mutations, with a majority of de novo mutations, resulting in GLUT-1 haploinsufficiency, have been described. Cases with an autosomal dominant transmission have been established and adults can exhibit symptoms of this deficiency. Ketogenic diet is an effective treatment of epileptic manifestations as ketone bodies serve as an alternative fuel for the developing brain. However, this diet is not effective on cognitive impairment and other treatments are being evaluated. The physiopathology of this disorder is partially unclear and its understanding could explain the clinical heterogeneity of GLUT-1 deficiency patients and lead to new treatments. This probably under-diagnosed deficiency should be suspected in children with unexplained neurological disorders including epilepsy, mental retardation and movement disorders and confirmed by a lumbar puncture and the direct sequencing of GLUT-1.
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PMID:[Glucose transporter type 1 (GLUT-1) deficiency]. 1880 65

COACH syndrome is a disorder characterized by hypoplasia of cerebellar vermis, oligophrenia, congenital ataxia, coloboma and hepatic fibrosis, and 21 cases have been reported to date. Here we describe the first Japanese case of COACH syndrome, who was diagnosed at the age of 37 years and never progressed to liver failure. The patient was found to have delayed developmental milestones at the age of 5 months and mental retardation at the age of 7 years. She had been treated for hepatopathy of unknown origin from the age of 22 years. She was admitted to Hiroshima University Hospital at the age of 37 years after the identification of esophageal varices on a routine upper endoscopy. Computed tomography of the abdomen revealed portal hypertension and splenomegaly, and liver biopsy showed liver fibrosis. In addition, she had coordination disorder and dysarthria. Brain magnetic resonance images revealed hypoplasia of cerebellar vermis. The final diagnosis was COACH syndrome. She underwent endoscopic injection sclerotherapy for esophageal varices. From that point until her death from ovarian cancer at the age of 41 years, the liver function tests were stable without an episode of hematemesis. Physicians should be aware of COACH syndrome when they examine young patients who present with hepatopathy, portal hypertension of unknown origin and cerebellar ataxia.
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PMID:The first Japanese case of COACH syndrome. 1926 Oct 4

Thyroid hormones are known to be essential for growth, development and metabolism. Recently mutations in the SLC16A2 gene coding for the monocarboxylate thyroid hormone transporter 8, MCT8, have been associated with Allan-Herndon-Dudley syndrome (AHDS), an X-linked condition characterized by severe mental retardation, dysarthria, athetoid movements, muscle hypoplasia and spastic paraplegia. Here we describe in detail the clinical and biochemical features in a boy affected by AHDS with severe neurological abnormalities and a novel de novo SLC16A2 gene insertion, 1343-1344insGCCC, resulting in a truncated protein lacking the last four transmembrane domains (TMDs) as well as the carboxyl cytoplasmic end. He presents mental retardation, axial hypotonia, hypertonia of arms and legs, paroxysmal dyskinesias, seizures. The endocrine phenotype showed low serum total and free thyroxine (T4), very elevated total and free triiodothyronine (T3) and normal thyrotropin (TSH) with blunted response to thyrotropin-releasing hormone (TRH). The latter finding was unexpected and suggested that the lack of functional MCT8 was counterbalanced at the thyrotrope cell level by high serum T3 concentration and/or by increased intrapituitary type 2 deiodinase (D2) activity. Our case constitutes a relevant contribution to better characterize this disorder and to elucidate the functional consequences of SLC16A2 gene mutations.
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PMID:Allan-Herndon-Dudley syndrome (AHDS) caused by a novel SLC16A2 gene mutation showing severe neurologic features and unexpectedly low TRH-stimulated serum TSH. 2071 92

We have identified a novel form of recessive ataxia that segregates in three children of a large consanguineous Saudi Arabian family. The three patients presented with childhood onset gait and limb ataxia, dysarthria and had limited walking without aid into their teenage years. Two patients developed epilepsy at 7 months without relapse after treatment, and mental retardation. Linkage studies allowed us to identify a single locus that segregated with the disease on chromosome 3q28-qter. Mutation screening of all coding sequences revealed a single nucleotide deletion, 2927delC, in exon 19 of the KIAA0226 gene, which results in a frame shift of the C-terminal domain (p.Ala943ValfsX146). The KIAA0226 gene encodes a protein that we named rundataxin, with two conserved domains: an N-terminal RUN domain and a C-terminal domain containing a diacylglycerol binding-like motif. The closest paralogue of rundataxin, the plekstrin homology domain family member M1, has been shown to colocalize with Rab7, a small GTPase associated with late endosomes/lysosomes, suggesting that rundataxin may also be associated with vesicular trafficking and signalling pathways through its RUN and diacylglycerol binding-like domains. The rundataxin pathway appears therefore distinct from the ataxia pathways involving deficiency in mitochondrial or nuclear proteins and broadens the range of mechanisms leading to recessive ataxias.
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PMID:Rundataxin, a novel protein with RUN and diacylglycerol binding domains, is mutant in a new recessive ataxia. 2082 35


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