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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expansion of trinucleotide repeats is now recognized as a major cause of neurological disease. At least seven disorders result from trinucleotide repeat expansion: X-linked spinal and bulbar muscular atrophy (SBMA), two fragile X syndromes of mental retardation (FRAXA and FRAXE), myotonic dystrophy, Huntington's disease, spinocerebellar ataxia type 1 (SCA1), and dentatorubral-pallidoluysian atrophy (DRPLA). The expanded trinucleotide repeats are unstable, and the phenomenon of anticipation, i.e., worsening of disease phenotype over successive generations, correlates with increasing expansion size. In this review, we compare the clinical and molecular features of the trinucleotide repeat diseases, which may be classified into two types. Fragile X and myotonic dystrophy are multisystem disorders usually associated with large expansions of untranslated repeats, while the four neurodegenerative disorders, SBMA, Huntington's disease, SCA1, and DRPLA, are caused by smaller expansions of CAG repeats within the protein coding portion of the gene. CAG repeats encode polyglutamine tracts. Polyglutamine tract expansion thus appears to be a common mechanism of inherited neurodegenerative disease. Although polyglutamine tract lengthening presumably has a toxic gain of function effect in the CAG trinucleotide repeat disorders, the basis of this neuronal toxicity remains unknown.
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PMID:Trinucleotide repeat expansion in neurological disease. 799 66

One hundred and twenty three children with difficult to control epilepsy (DCE) were studied. Etiological factors which predominated included an age of onset less than 2 years (71.5%), male sex (69%), mixed, secondarily generalized, or complex partial seizures (77%), mental retardation (64%) and neurological abnormalities (52%). Static neurological disease was seen in 63%, with only 17% having idiopathic disease. Identifiable epileptic syndromes were noted in less than half the children. The surface EEG was abnormal in 84%, and correlated with the clinical seizure type in 81%. CT and MRI were helpful in diagnosis in only 38 and 48%, respectively, and even less so in therapy decisions, 7 and 16%, respectively. Prior therapy revealed the use of polytherapy in 61% and suboptimal dosages in 78%. In the 100 patients with adequate follow up, 67% showed a good response, i.e., 35% complete and 32% more than 50% reduction in seizures. Only 11% were total nonresponders, and most were severely retarded. Major treatment strategies employed included switching to monotherapy, supranormal dosages and avoidance of sedative anticonvulsants. Side effects were noted in 41% with 8 cases being life threatening. Overall mortality was 4%. We concluded that risk factors for DCE included early age of onset, mental retardation and certain seizure types. EEG was more helpful than neuroimaging. Treatment responses were favorable, especially in those with normal intellect and the use of normal or high dose monotherapy.
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PMID:Difficult to control epilepsy in childhood--a long term study of 123 cases. 807 11

A door-to-door survey was made in Kelibia, Tunisia to determine the prevalence of major neurologic disorders, including epilepsy. The survey was made according to a World Health Organization (WHO) protocol (1981). All individuals responding positively to the screening tool were examined by a neurologic team using well-defined diagnostic criteria. One hundred forty-one individuals, alive on prevalence day (July 1, 1985), were identified as having active epilepsy, giving a crude prevalence ratio of 4.04 per 1,000 and an age-adjusted (on WHO population) prevalence ratio of 3.64 per 1,000. Prevalence ratios increase with age (in children and young adults with the highest prevalence ratio at approximately 20 years) and decrease after 40 years. The most frequently identified type was generalized convulsive seizures (93%). The most frequently associated conditions were cerebral palsy and mental retardation.
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PMID:Prevalence of epilepsy in Kelibia, Tunisia. 824 52

We report the findings of a total population survey of Thugbah community in the Eastern Province of Saudi Arabia (SA) to determine its point prevalence of neurological diseases. During this two-phase door-to-door study, all Saudi nationals living in Thugbah were first screened by trained interviewers using a pretested questionnaire (sensitivity 98%, specificity 89%) administered at a face-to-face interview. Individuals with abnormal responses were then evaluated by a neurologist using specific guidelines and defined diagnostic criteria to document neurological disease. The questionnaire was readministered blind by a neurologist to all those with abnormal responses and a 1-in-20 random sample of those without abnormal responses, respectively. The family members of an individual with an abnormal response were also screened to improve accuracy. A total of 23,227 Saudis (98% of the eligible subjects) were screened and those residing in Thugbah on the reference date (22,630) were used to calculate the point prevalence rates. Forty-two percent of those screened were in the first decade of life and only 1.5% were more than 60 years old. There were marginally more females (50.2%) than males (49.8%). Consanguineous marriages especially between first cousins were present in 54.6%. The demographic characteristics of Thugbah community were similar to those in other parts of SA. The overall crude prevalence ratio (PR) for all forms of neurological disease was 131/1,000 population. All subsequent PRs are per 1,000 population. Headache syndromes were the most prevalent disorder (PR 20.7). The PR for all seizure disorders was 7.60, and the epilepsies (6.54) were more frequent than febrile convulsions (0.84). Mental retardation, cerebral palsy syndrome, and microcephaly were common pediatric problems with PRs of 6.27, 5.30 and 1.99, respectively. Stroke, Parkinson's disease, and Alzheimer's disease were uncommon with respective PRs of 1.8, 0.27 and 0.22. Central nervous system (CNS) malformations (0.49) such as hydrocephalus and meningomyelocele were more prevalent than spinal muscular atrophy (0.13), congenital brachial palsy (0.13) and narcolepsy (0.04). Multiple sclerosis was rare (0.04). Osteoarthritis and low back pain syndromes were the main non-neurological conditions seen. The major medical diseases that may be neurologically relevant were diabetes mellitus, hypertension, and connective tissue disorders.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:A community survey of neurological disorders in Saudi Arabia: the Thugbah study. 827 77

Abnormalities of embryogenesis and nervous system development may cause or contribute to the development of childhood brain tumors. To identify genetic or environmental factors that may be associated with etiologies of childhood central nervous system tumors, we examined family histories of 165 children with such tumors for the presence of neurologic disorders, including neural tube defects, mental retardation, seizures, and central nervous system tumors, as well as other cancers and birth defects. Only 1 patient, with the neurofibromatosis-Noonan syndrome, was confirmed to have an underlying syndromic diagnosis associated with central nervous system tumorigenesis. Families of 2 probands with posterior fossa primitive neuroectodermal tumors reported relatives with olivopontocerebellar atrophy. Although increased incidences of study disorders were not identified in this population, it is possible that within individual families one or more of these disorders is related to childhood central nervous system tumorigenesis.
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PMID:Neurologic and other disorders in relatives of pediatric patients with CNS tumors. 853 75

A retrospective and prospective study was carried out on 54 children with gluten intolerance recognized 5-10 years ago. Coeliac disease (CD) was confirmed in 44 (81.5%) patients. The clinical picture in the observed children showed an evolution during the period of analysis. Intestinal symptoms are rare in adolescence (33%) while they are always present in the youngest children (initial diagnosis). At the time of the follow-up analysis, 67% of the patients demonstrated parenteral symptoms, mainly in the osteoarticular system, CNS, skin, mucous membranes and in only 33% children were the intestinal symptoms present. Over one third of the patients demonstrated body weight and height deficiency, 73% of boys and 39% of girls in age of pubescence had no maturity features. Neurological disorders were present in almost two thirds of the cases and about 5% of the children showed an evident mental retardation. Disruption of the gluten-free diet, frequent dietary errors and ineffective cooperation of the parents are the most probable reasons for physical and mental disturbances in the studied children. The obtained therapeutic results call for the creating of multi-disciplinary active care for children with gluten intolerance.
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PMID:A long-term study in children with a recognized gluten intolerance. 877 10

The prevalence of all neurological disorders in a Japanese town was calculated, with a result of 91.1 per 1,000 population. The prevalence of cerebrovascular disease was 28.8; myelopathy and/or radiculopathy caused by deformity of the spine or disc herniation, 23.9; neuralgia, 11.5; dementia, 10.4; peripheral nerve disturbance, 5.5; epilepsy, 4.4; Parkinson's disease, 2.0; mental retardation, 2.9; brain/spinal tumor, 1.4; headache, 10.8, and vertigo/dizziness, 4.4. The prevalence of headache and vertigo/dizziness was also calculated from the results of the questionnaires sent to inhabitants: headache, 79.6, and vertigo/dizziness, 60.8. Neurological disorders are common in Japan and likely to continue to increase.
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PMID:Prevalence of neurological disorders in a Japanese town. 881 3

Trinucleotide repeat expansion is increasingly recognized as a cause of neurogenetic diseases. To date, seven diseases have been identified as expanded repeat disorders: the fragile X syndrome of mental retardation both FRAXA and FRAXE loci), myotonic dystrophy, X-linked spinal and bulbar muscular atrophy, Huntington's disease, spinocerebellar ataxia type I, dentatorubral-pallidoluysian atrophy, and Machado-Joseph disease. All are neurologic disorders, affecting one or more regions of the neuraxis. Moreover, five of the seven (the last five above) are progressive neurodegenerative disorders whose strikingly similar mutations suggest a common mechanism of neuronal degeneration. In this article we discuss specific characteristics of each trinucleotide repeat disease, review their shared clinical and genetic features, and address possible molecular mechanisms underlying the neuropathology in each disease. Particular attention is paid to the neurodegenerative diseases, all of which are caused by CAG repeats encoding polyglutamine tracts in the disease gene protein.
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PMID:Trinucleotide repeats in neurogenetic disorders. 883 37

mental retardation: timing and thresholds; (italic)b(/italic)) endocrine dysfunction and developmental disabilities: dose and target implications; (italic)c(/italic)) attention-deficit disorder-ADHD and learning disabilities; and (italic)d(/italic)) new horizons: extending the boundaries. Support for the Rochester conference came from both public and private sources. The National Institute of Environmental Health Sciences (NIEHS), the National Institute of Child Health and Human Development, and the EPA represented the federal government. The conference also received grants from several foundations: the Jennifer Altman Foundation, the Heinz Family Foundation, the National Alliance for Autism Research, the Violence Research Foundation, the Wacker Foundation, and the Winslow Foundation. The second of these conferences helped launch a new Center for Children's Health and the Environment at the Mount Sinai School of Medicine. It was held in New York City on 24-25 May 1999, and was convened specifically to consider the intersection between neurodevelopmental impairment, environmental chemicals, and prevention. Over 300 health scientists, pediatricians, and public health professionals examined the growing body of evidence linking environmental toxins to neurobehavioral disorders. The conference title was Environmental Influences on Children: Brain, Development, and Behavior. The conference began by reviewing well-known examples of deleterious effects of environmental chemicals, including lead and PCBs, on children's brains. The conferees then considered the potential impact of environmental chemicals on neurological disorders with particular focus on ADHD, autism, and Parkinson's disease. The inclusion of Parkinson's disease was intended to signal the notion that exposures in early life may have an influence on the evolution of neurological disease in later life. Support for the Mount Sinai conference came from the Superfund Basic Research Program (NIEHS); The Pew Charitable Trusts; the Institute for Health and the Environment at the University of Albany School of Public Health; the Agency for Toxic Substances and Disease Research (ATSDR); the Ambulatory Pediatric Association; Myron A. Mehlman, PhD; the National Center for Environmental Assessment (EPA); the National Center for Environmental Health (CDC); the National Institute of Child Health and Human Development; the Office of Children's Health Protection (EPA); Physicians for Social Responsibility; The New York Academy of Medicine; The New York Community Trust; and the Wallace Genetic Foundation. The impact of environmental toxins on children's health has become a topic of major concern in the federal government. Eight new research centers in children's environmental health have been established in the past 2 years with joint funding from EPA and NIEHS. Clinical units that specialize in the treatment of children with environmentally induced illness have been developed across the nation with grant support from ATSDR. The American Academy of Pediatrics has just published its (italic)Handbook of Pediatric Environmental Health (/italic)((italic)17(/italic)), the "Green Book," which is available to pediatricians throughout the Americas. Children's environmental health has climbed to a critical position as we launch the new millennium. This monograph marks a significant milestone in the evolution of this emerging discipline.
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PMID:The developing brain and the environment: an introduction. 1085 30

Many of the risk factors previously identified for disorders such as Alzheimer's disease, periventricular leukomalacia, multiple sclerosis, stroke, cerebral palsy, mental retardation, and acquired learning and attention disorders ultimately may be shown to damage the central and peripheral nervous systems through activation of inflammatory mediators. The challenge to epidemiologists in the future is to expand use of epidemiologic methods to explore how immune-mediated insults produce CNS disorders in human populations. Studies of the association of use of nonsteroidal anti-inflammatory drugs with risk of Alzheimer's disease and those of the association of immune parameters with risk of cerebral palsy are excellent examples of how epidemiology can contribute to our understanding of the causes of neurologic and/or neurodevelopmental disorders. Many of the immune parameters of interest have short half-lives and are difficult to measure outside of the laboratory setting. Questions also remain as to the proper timing of measurements in relation to the initial insult and, in some cases, which tissue is the most appropriate to sample. These measurement issues will need to be resolved before use of immune biomarkers in epidemiologic studies of the etiologies of neurologic disorders can be fully realized. Epidemiologists are most likely to help identify ways to prevent neurologic disorders if they are knowledgeable about the molecular biology of inflammation, modulators of CNS vulnerability, and genetic polymorphisms that influence both inflammation and CNS vulnerability and are prepared to become adept at biomarker epidemiology. This does not necessarily compel them to gain extensive knowledge of neurobiology. Rather, neuroepidemiology in the 21st century will require increased collaboration between epidemiologists, neurologists, and neurobiologists.
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PMID:New research directions in neuroepidemiology. 1093 3


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