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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prevalence of mental retardation defined as IQ less than 70 has been estimated as ranging between 6.7-11.9 per thousand children in the Nordic countries. Etiological factors can be found in 80% of patients with severe mental retardation (IQ less than 50) and in 50% with mild mental retardation (IQ 50-70). Down's syndrome is the most common specific cause of mental retardation, followed by the Fragile X syndrome, which mainly affects boys. Since the middle of the 1980s Rett's syndrome has been recognized as the most frequent cause of progressive mental retardation in girls. Recent advances in the field of chromosomal disorders, metabolic diseases and clinical syndromes imply a need for new epidemiological research aimed at obtaining an updated picture of the heterogenous causes of mental retardation.
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PMID:[Mental retardation in children. Prevalence and etiology]. 156 94

Rett's syndrome (RS) is a neurologic disorder associated with severe mental deficiency and neurologic manifestations of cortical and extrapyramidal origin. The present report is a preliminary postmortem brain study that compares the levels of endogenous biogenic amines and selected neurotransmitter receptors in five cases with RS and six normal controls of similar age. The level of choline acetyltransferase activity was reduced in several cortical and subcortical regions. Endogenous levels of dopamine in the superior frontal and superior temporal gyri, occipital cortex, and putamen were reduced. The changes in specific neurotransmitter markers, particularly those associated with the basal ganglia and cortex, may underlie the progressive deterioration in motor and cognitive function characteristic of this progressive disorder.
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PMID:Altered neurochemical markers in Rett's syndrome. 165 85

Autism and dysphasia are behaviorally defined disorders of higher cerebral function which in preschool children share the common core symptom of impairment of language. In this study we describe the clinical characteristics of 314 autistic and 237 dysphasic nonautistic children evaluated by one child neurologist. There was no significant difference between autistic and dysphasic children in gestational age, birth weight, or prevalence of associated medical disorders, all of which were infrequent, although a positive history of resuscitation or ventilatory support was more common in dysphasic than autistic children (P = .03). As a group autistic children are more likely than dysphasic children to have language subtypes affecting central processing and formulation, a family history of psychiatric disorders and autism, and a history of regression of language and behavior. After excluding 12 girls with autistic symptoms who met the clinical criteria for Rett syndrome, we found that there was no significant difference in the number of autistic and dysphasic children with an abnormal sensorimotor examination. Girls with autism were more likely than boys to have severe mental deficiency (38% of autistic girls vs 23% of boys) (P = 0.012) and a motor deficit (27% vs 11%) (P = .0009).
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PMID:Autistic and dysphasic children. I: Clinical characteristics. 195 39

In a previously described population of 314 autistic and 237 dysphasic nonautistic children, after exclusion of 12 autistic girls with Rett syndrome, 14% (42 of 302) of autistic children and 8% (19 of 237) of dysphasic children had epilepsy (P = .03). The major risk factors for epilepsy were severe mental deficiency and the combination of severe mental deficiency with a motor deficit. In autistic children without severe mental deficiency, motor deficit, associated perinatal or medical disorder, or a positive family history of epilepsy, epilepsy occurred in 6% (10 of 160) which was analogous to the 8% (14 of 168) found in similar dysphasic nonautistic children. The language subtype of verbal auditory agnosia is associated with the highest risk of epilepsy in autistic (41%, 7 of 17) and dysphasic (58%, 7 of 12) children. The higher percentage of epilepsy in autistic girls, 24% (18 of 74) compared with boys 11% (25 of 228) (P = .003), is attributed to the increased prevalence of cognitive and motor deficit in girls. Once the risk attributable to associated cognitive and motor disabilities is taken into account, there is no difference in the risk of epilepsy between autistic and nonautistic dysphasic children.
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PMID:Autistic and dysphasic children. II: Epilepsy. 195 40

Eight patients who satisfied the following three criteria: 1) autistic behavior, 2) mental retardation and 3) stereotypic hand movements were evaluated. Four patients fulfilled the diagnostic criteria for the Rett syndrome developed by representatives of the International Rett Syndrome Association and the Center for Disease Control, Atlanta, USA. The other four Rett-like patients were atypical in the sense that the manifestations were incomplete or psychomotor development throughout the first 6 months of life was abnormal or the disease was heralded by infantile spasms with transient stereotypic hand movements or the baby was born with congenital microcephaly. All eight patients were girls. No laboratory test result specific for the Rett syndrome or Rett-like syndrome was obtained.
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PMID:The Rett and Rett-like syndromes: a broad concept. 195 70

Institutionalized adults with mental retardation (N = 297) were surveyed to determine the prevalence of symptoms of Rett syndrome. No symptom of the syndrome occurred more frequently in males than females. When symptoms were analyzed in clusters (e.g., severe mental retardation, no prenatal complications, walked before 15 months, and wide-based gait), no single cluster of symptoms appeared to differentiate males from females. However, as individuals, only females were found to meet the necessary criteria for a diagnosis of Rett syndrome. Symptoms were seen with equal frequency in this population and no one or two symptoms differentiated patients with and without Rett syndrome.
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PMID:Rett syndrome symptomatology of institutionalized adults with mental retardation: comparison of males and females. 204 52

An institution for the mentally retarded was surveyed to determine the prevalence rate of Rett syndrome (RS). Four patients with definite RS and one with probable RS were identified in a population of 350, yielding a prevalence rate of 1 in 87, about 1% of institutionalized male and female patients with mental retardation. In this population of patients with severe and profound mental retardation (N = 297), 138 females were surveyed, suggesting a prevalence rate among females of 1 in 34 in an institutional population of persons with mental retardation. Surveys of institutions for persons with mental retardation may be an effective method to identify adults with RS.
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PMID:A prevalence study of Rett syndrome in an institutionalized population. 233 4

Diagnostic criteria for Rett syndrome (RS) were developed by representatives of the International Rett Syndrome Association and the Centers for Disease Control for use in future clinical and epidemiological studies. Necessary criteria are: normal prenatal and perinatal period; normal psychomotor development through the first 6 months of life; normal head circumference at birth, with subsequent deceleration of head growth; loss of purposeful hand skills; severely impaired expressive and receptive language; apparent severe mental retardation; and gait apraxia and truncal apraxia/ataxia. Supportive criteria include breathing dysfunction, seizures, spasticity, scoliosis, and growth retardation. The diagnosis of RS is considered tentative until 2 to 5 years of age. The differential diagnosis includes other disorders associated with mental retardation, cerebral palsy, and seizure disorders. These diagnostic criteria for RS should foster reliable communication among investigators and enhance the epidemiological and clinical research of this important disorder.
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PMID:Diagnostic criteria for Rett syndrome. The Rett Syndrome Diagnostic Criteria Work Group. 245 7

In this paper, a rare neurological disorder seen exclusively in girls is described. According to its progress and clinical behaviour, a syndrome resembles autism. The disease was reported in 1966 by A. Rett from Vienna. The syndrome often remains unrecognized because of its low incidence or is mistaken for autism, mental retardation and cerebral paralysis. The table of differential diagnosis of this disease in relation to autism is given. We report on a 5-year-old girl from Zrenjanin who was admitted to the Division for Autism, Psychiatric Hospital Jankomir, Zagreb. The diagnosis of Rett's syndrome was established in this patient whose initial description documented autism. The medications have shown to be without effect, except anticonvulsive drugs and ketogenic diet. Physical, occupational and musical therapy as well as hydrotherapy were applied.
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PMID:[Rett's syndrome--differential diagnosis of autism in a case report]. 263 9

We report 6 cases of Rett syndrome, a disorder that occurs only in girls and is characterized by slowly progressive deterioration of higher brain function, with dementia and autistic behavior, loss of purposeful use of the hands and deceleration of head growth. We consider interesting this report because Rett syndrome would be an important cause of mental retardation in girls, which has been overlooked until few years ago.
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PMID:[Rett syndrome. A frequent cause of progressive mental retardation in girls]. 272 88


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