Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rett syndrome (RTT) is an X-linked dominant neurodevelopmental disorder characterized by regression in cognition and adaptability with autistic behavior, stereotypical hand movements, epilepsy and ataxia. Over 120 different mutations in the methyl-CpG binding protein 2 gene (MECP2) have been reported in patients with RTT, but a genotype-phenotype correlation has not been established. We have studied MECP2 mutations in 142 Japanese sporadic patients diagnosed clinically as having RTT. Forty different mutations in MECP2 have been detected in 103 female patients. Common mutations were four missense mutations (T158M,P152R, R133C and R306C) observed in 34 cases and four nonsense mutations (R168X, R255X, R270X and R294X) detected in 38 cases. Among these, R133C, R306C, and R294X were associated with atypical RTT including the preserved speech variant type, T158M and R168X with typical clinical features of RTT, and P152R, R255X, and R270X with severe developmental delay. These results suggest a genotype-phenotype correlation RTT. However, a large scale study of adult RTT patients is required to determine more precisely the influence of MECP2 mutation types on the natural history and clinical phenotypes of RTT.
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PMID:[Mutation spectrum and genotype-phenotype correlation of MECP2 in patients with Rett syndrome]. 1203 10

Rett syndrome is a severe, genetically determined disease of early childhood which produces a defined clinical phenotype in girls. The main clinical manifestations include lesions affecting speech functions, involving both expressive and receptive speech, as well as motor functions, producing apraxia of the arms and profound abnormalities of gait in the form of ataxia-apraxia. Most investigators note that patients have variability in the severity of derangement to large motor acts and in the damage to fine hand movements and speech functions. The aims of the present work were to study disturbances of speech and motor functions over 2-5 years in 50 girls aged 12 months to 14 years with Rett syndrome and to analyze the correlations between these disturbances. The results of comparing clinical data and EEG traces supported the stepwise involvement of frontal and parietal-temporal cortical structures in the pathological process. The ability to organize speech and motor activity is affected first, with subsequent development of lesions to gnostic functions, which are in turn followed by derangement of subcortical structures and the cerebellum and later by damage to structures in the spinal cord. A clear correlation was found between the severity of lesions to motor and speech functions and neurophysiological data: the higher the level of preservation of elements of speech and motor functions, the smaller were the contributions of theta activity and the greater the contributions of alpha and beta activities to the EEG. The possible pathogenetic mechanisms underlying the motor and speech disturbances in Rett syndrome are discussed.
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PMID:Speech and motor disturbances in Rett syndrome. 1224 51

Rett syndrome is a progressive, usually sporadic and rarely familial, disabling neurodevelopmental disorder with onset in early childhood presenting clinically with mental retardation, behavioral changes, late movement disturbances, loss of speech and hand skills, ataxia, apraxia, irregular breathing with hyperventilation while awake, and frequent seizures. It occurs almost exclusively in females with an estimated prevalence of 1 in 10-22000 births and is considered a manifestation of defective brain maturation caused by dominant mutation of the MeCP2 gene encoding the transcriptional repressor methyl-CpG-binding protein 2 related to the Xq28 locus. Although many different mutations of this protein are being studied in humans and in mice, the molecular pathogenesis of this disorder remains unclear. Electroencephalography is abnormal in the final stages of the syndrome. Neuroimaging showing brain atrophy may be required for differential diagnosis that includes neurodegenerative and metabolic disorders. Neuropathology shows decreased brain growth and reduced size of individual neurons, with thinned dendrites in some cortical layers and abnormalities in substantia nigra (decreased neuromelanin content), suggestive of deficient synaptogenic development, probably starting before birth. Neurometabolic changes include reduced levels of dopamine, serotonin, noradrenalin, choline acetyltransferase (ChAT), nerve growth factors, endorphines, glutamate, and other amino acids and their receptor levels in brain. Current treatment includes symptomatic, anticonvulsive and physiotherapy.
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PMID:Rett Syndrome -- an update. 1276 63

Angelman syndrome (AS) is an imprinted neurobehavioral disorder characterized by mental retardation, absent speech, excessive laughter, seizures, ataxia, and a characteristic EEG pattern. Classical lesions, including deletion, paternal disomy, or epigenetic mutation, are confirmatory of AS diagnoses in 80% of cases. Loss-of-function mutations of the UBE3A gene have been identified in approximately 8% of AS cases, failing to account for the remaining patient population, and there appears to be a higher prevalence of mutations in familial than sporadic cases. We screened UBE3A in 45 index cases of AS without obvious 15q11-13 abnormalities. Pathological mutations were identified in 3/6 (50%) familial and 4/39 (>10%) sporadic cases. By combining our data with those of the literature, we demonstrate statistically that the frequency of UBE3A mutations is significantly higher in the familial than sporadic subsets of AS. This indicates that an independent molecular mechanism or 'phenocopy' exists for the sporadic group. Rett syndrome (RS), caused by mutations of the MECP2 gene, and patients with deletions of 22q13.3 --> qter, have overlapping clinical features with AS. We screened 24 of the sporadic AS cases without detectable UBE3A mutations for mutations of MECP2, but found none. A separate cohort of 43 atypical patients with features common to AS and RS, in whom 15q11-13 lesions and 22q13.3 --> qter deletion had been ruled out, were also screened for MECP2 mutations. One male patient was mosaic for a frameshift mutation of this gene (previously reported). While MECP2 mutations can cause a phenotype reminiscent of AS in rare cases, they fail to account for the excess of sporadic patients with a definitive clinical diagnosis of AS.
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PMID:Investigation of UBE3A and MECP2 in Angelman syndrome (AS) and patients with features of AS. 1498 18

In neurodevelopmental disorders, the characteristic symptoms appear age-dependently along with the functional and morphological development of the affected neurons and the neuronal pathways. Most of them have the primary lesion in the subcortical structures as these mature earlier, which include the aminergic neurons of the brainstem and the midbrain having important roles for development of the higher cortical function (HCF). Thus, to clarify the pathophysiologies of the symptoms appearing age-dependently makes it possible to demonstrate the process of development of the HCF. Here, I reviewed the characteristic symptoms and their pathophysiologies of Rett syndrome, DYT-1, autosomal dominant GTP cyclohydrolase I (ADGCH I) deficiency, Tourette syndrome (TS) and Early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH), and suggested that the brainstem aminergic neurons modulating the locomotion have roles for development of the frontal cortex, the dopaminergic neurons and basal ganglia pathways involving in the action dystonia for motor execution and the serotonergic and the dopaminergic neurons projectioning to the nonmotor basal ganglia thalamocortical circuits for development of the frontal area, the targets of the circuits. While, postural dystonia, tics in GTS and symptoms in EAOH reflect the development of the causative neurons and the neuronal systems.
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PMID:[Visual child neurology]. 1515 53

Lamotrigine is a broadly effective antiepileptic drug in mono- and add-on therapy for children and adolescents with focal and generalized epilepsies. Some epileptologists consider lamotrigine as the drug of primary choice in older school children and adolescents because of its good tolerability (no increase of body weight, no impairment of cognitive functions, due to new data probably no teratogenic properties). Lamotrigine can be used with good efficacy in numerable epilepsy diseases, such as tuberous sclerosis, juvenile neuronal lipofuscinosis and Rett syndrome. The first studies show that lamotrigine is also effective in children under 2 years of age. For therapy of difficult-to-treat epilepsies the combination of lamotrigine with valproate has proved as especially useful. This clinical observation is supported by new results of animal experiments. The dose-dependant and typical CNS side effects vertigo, ataxia, nausea, tremor and diplopia are found most frequently. The rate of allergic skin rashes which was very high before 1998 has decreased markedly by new dosage guidelines and is now as low as in older antiepileptic drugs. Lamotrigine does not impair cognitive functions, especially not memory and language. It has mood-stabilizing features and may improve quality of life. In animal experiments lamotrigine shows antiepileptogenic and neuroprotective effects.
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PMID:[Optimizing epilepsy therapy in children and adolescents with lamotrigine]. 1603 48

Rett syndrome (RTT) is a neurodevelopmental disorder characterized by cognitive regression, loss of purposeful hand movements and speech, stereotypies, ataxia, seizures, mental retardation and acquired microcephaly. Mutations in MECP2, encoding methyl-CpG-binding protein 2, are responsible for approximately 90% of classic RTT cases. RTT displays phenotypic overlap with Angelman syndrome, a disorder caused by loss of expression of the imprinted gene UBE3A. MeCP2 binds to methylated DNA and may alter the expression of imprinted genes, thereby suggesting a mechanistic link between the two disorders. Here, we tested the hypothesis that MeCP2 deficiency affects expression of Ube3a in mouse models of RTT. As Ube3a is only imprinted in brain, we evaluated Ube3a expression in brains of 15 different litters of neonatal or 8-week-old male Mecp2 mutant mice by real-time quantitative RT-PCR and western blot analysis. We found no significant differences between Mecp2(tm1.1Bird/Y) or Mecp2(tm1.1Jae/Y) mutants and their wild-type male siblings that served as negative controls. In positive control mice carrying a maternally inherited Ube3a deletion, Ube3a sense transcript and protein levels were drastically reduced. Our data contrast with two recent reports of substantially decreased Ube3a expression in brain tissues of MeCP2-deficient mice. We, therefore, challenge the conclusion that decreased UBE3A/Ube3a expression contributes to the pathophysiology of RTT.
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PMID:Ube3a expression is not altered in Mecp2 mutant mice. 1675 45

Individuals with Rett syndrome (RS) present a vast array of orthopedic and neurological difficulties. Typical problems, which may need to be addressed, when treating this population are functional limitations, low cardiovascular capacity, hypotonia, ataxia, apraxia, loss of transitional movements, spasticity, scoliosis and/or kyphosis, loss of ambulation, loss of hand function, foot deformities, and spatial disorientation. Coping with such difficulties and overcoming the associated limitations carry a wearisome task for the individual with Rett as well as for her family. An informed and intensely applied physical therapy regime can help the child and the family cope and even overcome the above-mentioned limitations. The present article presents some insights regarding the intervention with individuals with RS, an overview of typical neuromuscular problems associated with RS, and appropriate suggestions pertaining to clinical intervention that have been found to contribute to this population's well-being. The information presented is mainly based on the clinical knowledge of the authors.
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PMID:Physical therapy intervention for individuals with Rett syndrome. 1704 20

RNA is not a simple intermediate between DNA and proteins. RNA is widely transcribed from a variety of genomic regions, and researchers are extensively exploring the functional roles and the regulations of non-coding RNAs and small RNAs including siRNAs and mRNAs. In addition, the human genome project disclosed that we humans carry as few as approximately 22,000 genes. Humans employ tissue-specific and developmental stage-specific alternative splicing to generate a large variety of proteins in a specific cell at a specific developmental stage. Neurological disorders are not the exceptions that can escape from aberrations of the splicing machinery. A large variety of neurological disorders is causally associated with RNA pathologies, but this lecture was mostly focused on aberrant splicings due to pathological alterations of splicing cis- and trans-elements. The neurological diseases covered include congenital myasthenic syndromes, genetic forms of Parkinson's disease, spastic paraplegia, myotonic dystrophy types 1 and 2, sporadic Alzheimer's disease, facioscapulohumeral dystrophy, fragile X-associated tremor/ ataxia syndrome, Rett syndrome, Prader-Willi syndrome, spinocerebellar atrophy type 8, and Waardenburg-Shah syndrome. Potential therapeutic modalities targeting RNA are addressed on congenital myasthenic syndromes, Duchenne muscular dystrophy, spinal muscular atrophy, and familial dysautonomia.
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PMID:[RNA pathologies in neurological disorders]. 1821 Aug 2

Rett syndrome (RTT) is a severe developmental-neurological disorder, characterized by profound and progressive loss of intellectual functioning, occurring after a period (of at least 6 months) of normal development with classic stereotype hand movements, gait ataxia, jerky truncal ataxia, deceleration of brain and body organ growth and cardiac dysautonomia. Pathogenesis of sympathetic overactivity in RTT is unknown, but a previous study observed increased plasma leptin levels in Rett girls and it is well known the role of leptin in the regulation of sympathetic nervous system activity. Aim of our study is to evaluate a relationship between plasma leptin levels and sympathetic activity in RTT. Thirty-two female patients (12.1+/-6.3 years), affected by RTT were enrolled in the study. In all the subjects, we analyzed heart rate variability, QT corrected interval and plasma leptin levels. A significant correlation was found between plasma leptin levels and LF/HF (expression of sympatho-vagal balance) (Spearman r=0.44, p=0.001). There is also a significant negative correlation between HF component (expression of vagal activity) and plasma leptin levels (Spearman r=-0.037, p=0.03) and a positive correlation between LF component and plasma leptin levels (Spearman r=0.047, p=0.01). These results show that in RTT higher plasma leptin levels appear to be associated with sympathetic overactivity, suggesting a role for leptin in cardiac dysautonomia.
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PMID:Sympathetic overactivity and plasma leptin levels in Rett syndrome. 1822 48


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