Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MENTAL RETARDATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed2001

NXF5, a novel member of the nuclear RNA export factor family, is lost in a male patient with a syndromic form of mental retardation.

BACKGROUND: Although X-linked mental retardation (XLMR) affects 2%-3% of the human population, little is known about the underlying molecular mechanisms. Recent interest in this topic led to the identification of several genes for which mutations result in the disturbance of cognitive development. RESULTS: We identified a novel gene that is interrupted by an inv(X)(p21.1;q22) in a male patient with a syndromic form of mental retardation. Molecular analysis of both breakpoint regions did not reveal an interrupted gene on Xp, but identified a novel nuclear RNA export factor (NXF) gene cluster, Xcen-NXF5-NXF2-NXF4-NXF3-Xqter, in which NXF5 is split by the breakpoint, leading to its functional nullisomy. The predicted NXF5 protein shows high similarity with the central part of the presumed mRNA nuclear export factor TAP/NXF1. Functional analysis of NXF5 demonstrates binding to RNA as well as to the RNA nuclear export-associated protein p15/NXT. In contrast to TAP/NXF1, overexpression studies localized NXF5 in the form of granules in the cell body and neurites of mature hippocampal neurons, suggesting a role in mRNA transport. The two newly identified mouse nxf homologs, nxf-a and nxf-b, which also map on X, show highest mRNA levels in the brain. CONCLUSIONS: A novel member of the nuclear RNA export factor family is absent in a male patient with a syndromic form of mental retardation. Although we did not find direct evidence for the involvement of NXF5 in MR, the gene could be involved in development, possibly through a process in mRNA metabolism in neurons.

Active Transport, Cell Nucleus↗
PubMed1993

Development of conceptual knowledge in children with mental retardation.

Nine and 14-year-old children with mild mental retardation and children without mental retardation matched for mental and chronological age were first shown a novel category made up of five visual figures. They were then given a recognition test with a set containing the previously presented figures, novel category members, and the category prototype. The relative contribution of prototypical and exemplar-specific information to subjects' performance on the recognition test was evaluated. Results showed that the children without mental retardation employed both forms of information in arriving at a recognition decision whereas both of the retarded groups tended to rely only on prototype information. Use of exemplar-specific information was also found to be positively correlated with IQ and, in particular, with measures of short-term memory span.

Adolescent↗
PubMed2002

The Xq22 inversion breakpoint interrupted a novel Ras-like GTPase gene in a patient with Duchenne muscular dystrophy and profound mental retardation.

A male patient with profound mental retardation, athetosis, nystagmus, and severe congenital hypotonia (Duchenne muscular dystrophy [DMD]) was previously shown to carry a pericentric inversion of the X chromosome, 46,Y,inv(X)(p21.2q22.2). His mother carried this inversion on one X allele. The patient's condition was originally misdiagnosed as cerebral palsy, and only later was it diagnosed as DMD. Because the DMD gene is located at Xp21.2, which is one breakpoint of the inv(X), and because its defects are rarely associated with severe mental retardation, the other clinical features of this patient were deemed likely to be associated with the opposite breakpoint at Xq22. Our precise molecular-cytogenetic characterization of both breakpoints revealed three catastrophic genetic events that had probably influenced neuromuscular and cognitive development: deletion of part of the DMD gene at Xp21.2, duplication of the human proteolipid protein gene (PLP) at Xq22.2, and disruption of a novel gene. The latter sequence, showing a high degree of homology to the Sec4 gene of yeast, encoded a putative small guanine-protein, Ras-like GTPase that we have termed "RLGP." Immunocytochemistry located RLGP at mitochondria. We speculate that disruption of RLGP was responsible for the patient's profound mental retardation.

Adolescent↗
PubMed2000

Characteristics of mentally retarded criminal offenders in Northern Taiwan.

The characteristics and criminal behavior in mentally retarded individuals remain largely unstudied. This retrospective study sought to establish a set of reference of criminal behavior characteristics in an ethnic Chinese mentally retarded group. Data were collected from forensic psychiatric evaluation of 32 mentally retarded offenders. Of the 32 offenders, only four (12.5%) cases were female. Mean age at the time of the offenses was 31. By IQ testing, 23 (71.9%) of the group fell into the mild mental retardation range, seven (21.9%) into the moderate mental retardation range, and two (6.2%) into the severe mental retardation range. Nineteen (59.3%) of the group also suffered from additional mental disorder. Eight (25%) had definite neurological deficit. Fourteen (43.8%) were repeat offenders. A total of 24 (75%) of the offenders had committed crimes against property, with 13 having committed petty theft. Furthermore, the pattern of offending shows differences from that of the general population or other mental disorders. The property offenses, especially petty theft and arson, were frequently seen. There was no noteworthy above average frequency of sexual offenses.

Adolescent↗
PubMed1983

Screening for fra(X)(q) in a population of mentally retarded males.

Among 242 institutionalized mentally retarded males in Northern Germany screened for fra(X)(q), 15 (6.2%) with severe mental retardation expressing fra(X)(q) were detected. One patient displayed Klinefelter's syndrome in addition. All fra(X)(q) males showed the typical facial signs, but three of the adults did not express macroorchidism. A preliminary estimation of an overall frequency of 1:2000 males for the fra(X)(q) condition is suggested.

Adolescent↗
PubMed1992

Is outerdirectedness employed in a harmful or beneficial manner by students with and without mental retardation?

Factors affecting the desirability of an outerdirected problem-solving approach were examined in 56 students with mental retardation and 53 MA-matched students without mental retardation in order to determine whether these groups employed outerdirectedness in a useful or detrimental manner. Students without mental retardation were sensitive to characteristics of the criterion task, such as task difficulty and usefulness of the external cue, and used outerdirected approaches in a strategic and beneficial manner. Characteristics of the task did not affect use of outerdirected approaches by students with mental retardation, who relied on all types of external cues, task-relevant as well as incidental and misleading, much more than did students without mental retardation. Yet their greater outerdirectedness was strongly affected by the difficulty of the preceding task. After easy initial tasks, students with mental retardation were no more outerdirected than their counterparts without mental retardation. Implications of the findings for lowering the harmful reliance of students with mental retardation on external cues were discussed.

Achievement↗
PubMed1992

Ullrich-Turner syndrome with a small ring X chromosome and presence of mental retardation.

Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference less than 10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A "triangular" face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45,X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS.

Adolescent↗
PubMed2000

The abilities of children with mental retardation to remember personal experiences: implications for testimony.

Investigated the abilities of children with mental retardation to remember the details of a personally experienced event. A simulated health check was administered to 20 children with mental retardation and 40 normally developing children, half matched on mental age (MA) and half matched on chronological age (CA) with the children with mental retardation. The children's memory was assessed immediately after the health check and 6 weeks later. Overall, the children with mental retardation accurately recalled the health check features, provided detail, and resisted misleading questions about features that did not occur. The group with mental retardation performed similarly to the MA matches on virtually all of the memory variables. The children with mental retardation performed worse than the CA matches on most of the memory variables, although they were able to recall a similar number of features. The findings are discussed in terms of the ability of children with mental retardation to provide accurate testimony.

Adolescent↗
PubMed1993

Conceptual and psychometric concerns about the 1992 AAMR definition of mental retardation.

The new American Association on Mental Retardation (AAMR) definition of mental retardation (Luckasson et al., 1992) represents a radical departure from previous definitions. In the present paper we examined the extent to which the new definition provides decision rules to guide clinicians and researchers in classification efforts. We concluded that the IQ criterion of 75 will increase the proportion of the general population eligible near the cut-off score. Moreover, the 10 adaptive skill areas adopted fail to consider developmental factors and cannot be assessed reliably with current scales. Proposed differentiation by levels of needed supports is also challenged as being imprecise and not amenable to reliable measurement. Implications of this new definition for diagnostic practices and research endeavors were explored.

Activities of Daily Living↗
PubMed1997

[Neurometabolic diagnosis of mental retardation].

Eighty-five percent of mentally retarded people have mild mental retardation (MR). Severe MR has a probable or definitive causes in 80% of cases. 2/3 are prenatal, 1/6 perinatal and 1/6 postnatal. Metabolic disorders may manifest as MR and its progressive nature often is not observed at the time of evaluation. MR is a prominent finding of many hereditary metabolic diseases, but only a fraction of MR seen in daily practice is due to inborn errors of metabolism. Medical conditions may present as MR without major extraneurological changes. In the investigation of MR, developmental milestones of affected children as well as detailed physical and neurological exam looking for physical characteristics, and performance of routine and special screening tests should be done. The metabolic screening tests (urine and/or blood) is very helpful. Use of tandem MS or acylcarnitine profile in blood for the diagnosis of organic acidurias and aminoacidurias can be done in 3 minutes per blood sample, with more than 20 conditions simultaneously tested. Blood spots in filter paper, once dried, are stable for weeks and can be sent by regular air mail, with low processing costs. Its future as a mass screening tool seems promising.

Humans↗
PubMed1989

Individual psychotherapy with mentally retarded individuals: a review and call for research.

Although most mental health professionals doubt the capacity of mentally retarded patients to benefit from psychotherapy, a review of case studies, writings, and research revealed that mentally retarded patients responded positively to treatment. Practitioners familiar with this population developed six major recommendations for adapting psychotherapeutic approaches to mentally retarded patients. In order for therapy to be successful, it is recommended that clinicians adapt standard technique to the patient's cognitive level, be directive in approach, be flexible during therapy, engage significant others in the therapeutic process, carefully manage transference and countertransference issues, and directly address the issue of mental retardation as a disability. The results of three research studies suggested that mentally retarded patients benefit from psychotherapy, although a fourth study showed negative results. There is a great need for systematic research to develop a knowledge base to support the growing applications of psychotherapeutic methods to this population.

Humans↗
PubMed1994

[Preliminary analysis of factors causing mental retardation in China].

Analysis of the data collected from national sampling survey of the mental retarded in 1987 showed: (1) prevalence of mental retardation in China was 12.68/1,000, (2) its causes mainly included hereditary diseases, cerebral diseases, malnutrition, pregnant infection and birth trauma for children and senile dementia for the elderly aged 60 or over, (3) severe mental retardation was mainly caused by cerebral diseases and developmental deformity in the country, and (4) the causes for 40.1% of the mental retarded persons remained unknown. Based on the researches at home and abroad, a series of major preventive measures for mental retardation have been put forward, they included: (1) to promote better birth and better rearing, vaccination, proper nutrition for pregnant mothers and infants, and safety education as focuses in primary prevention, (2) to detect early and timely treat cerebral diseases and nutritional deficiency, to strengthen antenatal diagnosis and early screening for inborn metabolic diseases as secondary prevention, and (3) to strengthen education, behavioral training and psychological rehabilitation, and to provide community-based rehabilitation service for the mental retarded as tertiary prevention.

Adolescent↗
PubMed1978

Sentence structures of trainable and educable mentally retarded subjects.

Educable and trainable mentally retarded children were administered a story completion task that elicits 14 grammatical structures. There were more correct responses from educable than from trainable mentally retarded children. Both groups found imperatives easiest, and future, embedded, and double-adjectival structures most difficult. The children classed as educable produced more correct responses than those termed trainable for declarative, question, and single-adjectival structures. The cognitive and linguistic processing of both groups is discussed as are the implications for language remediation.

Child↗
PubMedDate not supplied

Physical activity of adults with mental retardation: review and research needs.

OBJECTIVE: To characterize physical activity levels of adults with mental retardation and identify limitations in published research. DATA SOURCES: Key word searches for "mental retardation," "intellectual disability," "learning disability," or "developmental disability" combined with "physical activity" or "habitual exercise" identified articles from MEDLINE, Academic Search Elite, Psych Articles, Health Source, and SPORT Discus. This produced a total of 801 citations. STUDY INCLUSION AND EXCLUSION CRITERIA: Published English-language literature that quantitatively measured physical activity levels of adults with mental retardation was included in this review. Fourteen articles met this criterion. DATA EXTRACTION: Characteristics of participants, study design, outcome measures, methods of analyses, and findings in terms of percentages, step counts, and accelerometer output were extracted. DATA SYNTHESIS: Data were synthesized to identify the percentage of adults with mental retardation who met published health-related physical activity criteria and compare them with adults without mental retardation and to examine study limitations. RESULTS: The studies with the greatest rigor indicate that one-third of adults or fewer with mental retardation were sufficiently active to achieve health benefits. However, data are insufficient to determine whether adults with mental retardation are less active than the general community. CONCLUSIONS: Future research would be enhanced by including appropriately powered representative samples, by including comparison groups, by validating physical activity questionnaires, and by determining the accuracy of proxy respondents.

Adult↗
PubMed2004

Subtelomeric rearrangements: results from FISH studies in 84 families with idiopathic mental retardation.

BACKGROUND: The etiology of mental retardation (MR) is unexplained in at least 50% of cases. Recently it was shown that subtle telomeric rearrangements may be a common cause of idiopathic mental retardation (IMR). MATERIAL/METHODS: We studied 84 families with IMR and unspecific clinical features suggesting chromosomal aberration, including 59 patients with moderate to severe MR and 24 with mild MR. One healthy father of three deceased, severely MR children was also included. Fluorescence in situ hybridization (FISH) using 41 subtelomeric probes (the Chromoprobe Multiprobe--T System) was performed in all patients. RESULTS: Ten (11.9%) subtle chromosome rearrangements were identified. Nine (10.7%) were subtelomeric abnormalities. Seven were familial, with six of paternal origin. All but one were products of parental balanced reciprocal translocation or inversion. Retrospective G-banding analysis showed that six of the nine rearrangements could be seen or suspected at the 450-550 band levels. Subtelomeric abnormalities were recognized in six patients with severe/moderate (including the father of children with severe MR) and in three with mild MR. CONCLUSIONS: Our results confirm previous findings on the importance of subtelomeric rearrangements in the etiology of MR. They also show the diagnostic utility of subtelomeric FISH in detecting subtle telomeric rearrangements in IMR cases. The high proportion of familial rearrangements emphasizes their importance for genetic counseling. FISH screening was more reliable and efficient in identifying subtle telomeric abnormalities than G-banding analysis. However, as many of the subtelomeric abnormalities could be detected in retrospect even at the 550 band level, high-resolution G-banding analysis should always precede subtelomere assay. This is important for a better estimation of the real frequency of cryptic subtelomeric abnormalities.

Chromosome Aberrations↗
PubMed2006

[Monogenic causes of X-linked mental retardation].

INTRODUCTION AND DEVELOPMENT: The term X-linked mental retardation (XLMR) refers to a heterogeneous group of conditions that, on the basis of their presenting symptoms, have traditionally been classified as being syndromic (SMR) and non-syndromic or non-specific (XMR). The prevalence of XLMR in males is estimated to be 10%, excluding fragile X syndrome, which is the most common monogenic cause. There are over 100 genes involved in XLMR. In this work we review some of the phenotypes and genes involved in SMR. A small stature and coarse features indicate a suspected case of Coffin-Lowry syndrome, which is secondary to mutations of the RPS6KA3 or RSK2 genes. Cerebellar hypoplasia points towards alterations of the OPHN1 gene. In males with coarse features and genital abnormalities screening for alpha thalassemia must be carried out; this association results from mutations in the ATRX gene. Of the genes involved in mental retardation and epilepsy, the most notable are SLC6A8 (which triggers a deficit in creatine transport when altered and which is easily detected with respect to its biochemistry) and ARX (also associated to lissencephaly and dystonia of the hands). Mutations in the PQBP1 and JARID1C genes have been identified in patients with mental retardation associated to microcephaly and short stature. A high level of T3 hormone points towards defects in the SLC16A2 gene. Some of these genes have also been implicated in XMR, which makes this distinction less clear molecularly speaking. CONCLUSIONS: Systematic screening of all the genes involved in XLMR is not possible in clinical praxis today. It is important to search for differential phenotypic features in males with mental retardation that guide the study towards specific genes. Identification of the molecular defect will allow for correct genetic counselling. DNA microarrays for the study of different mutations in a large number of genes involved in mental retardation are the great hope for the future.

Humans↗
PubMedDate not supplied

The clinical phenotype in institutionalised adult males with X-linked mental retardation (XLMR).

In an institutionalised population of 471 mentally retarded adult residents (436 males and 35 females), 22 males (i.e. 5 % of the male population) had XLMR, accounting for 36.1 % of the residents diagnosed with a monogenic disorder (n = 61). Fragile X syndrome (FRAXA) was diagnosed in 16 residents, X-linked mental retardation with marfanoid habitus (Lujan-Fryns syndrome) in 2, and non-specific X-linked mental retardation (MRX) in 4 males. The 4 MRX-patients included 3 male sibs of a family, carrying a mutation in the IL-1 receptor accessory protein-like gene, and one male patient member of the MRX-44 family (linkage with LOD-score of 2.90). In the group of 215 males with idiopathic mental retardation (MR), family histories and pedigree data were compatible with XLMR in 35 males (35/215 = 16.3 %) from 32 families. Of these 35 males, 5.7 % were microcephalic with dysmorphic features and 5.7 % macrocephalic; micro-orchidism and macro-orchidism were each found in 11.4 %. One macrocephalic male had also macro-orchidism and dysmorphic features. In this study, the diagnosis of XLMR could thus be proposed in 57 males i.e. 13.1 % of the total male population. The clinical phenotype, behavioural problems and follow-up data in these different subgroups of XLMR are presented.

Adult↗
PubMed2000

[Sex-linked mental retardation].

It has long been known that among patients with mental retardation males outnumber females. This is the result of mutations in X-chromosomal genes: X-linked mental retardation. Its prevalence has been estimated as 1.8/1000 males with a carrier frequency of 2.4/1000 females. X-linked mental retardation is divided into syndromic and non-specific types. At present there are about 135 syndromic forms known of 26 of which the responsible genes and mutations have been found. 8 genes are known in which mutations have been found in non-specific X-linked mental retardation. It is estimated that about 100 genes are involved in the latter. These genes are in particular involved in the function of the central nervous system. The development of a complete genetic map of the X-chromosome and the introduction of microarray techniques will in the short term enormously enhance the elucidation of X-linked mental retardation.

Female↗