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The differentially expressed C21orf5 gene in the medial temporal-lobe system could play a role in mental retardation in Down syndrome and transgenic mice.

Mental retardation represents the more invalidating pathological aspect of Down syndrome, DS, and has a hard impact in public health. Modifications in DS brain, concerning abnormal size, neuronal differentiation, and cell density, cause changes in the neurophysiology and behavior of DS patients, and could be determined by dosage imbalance of genes localized in the DS critical region, DCR. Among these genes, C21orf5 showed high homology with Caenorhabditis elegans Pad1 involved in cellular differentiation and patterning. To shed light on C21orf5 role in DS, we performed molecular characterization of human and mouse orthologs, their spatio-temporal expression during development and in adult, and overexpression in DS and transgenic mice. C21orf5 was widely expressed early in embryogenesis in the nervous system. Later, its expression became differential and increased in mesencephalon and rhomboencephalon. This developmental expression profile evolves selectively in adult brain with higher signals in hippocampus, cerebellum, perirhinal, and entorhinal cortex, compared to the other cortical regions. Cellular specificity was detected in hippocampus with higher C21orf5 mRNA level in CA3 cells. Our findings appoint C21orf5 as candidate gene for mental retardation: Its overexpression in DS cells may contribute to gene imbalance in DS.Its specific expression in normal and its mirroring pattern in transgenic mice correspond to abnormal regions in DS patients and to neurological phenotype of transgenic mice. Altered cortical lamination in transgenic mice and the Pad1 ortholog function suggest a potential role of C21orf5 in cell differentiation. Its patterned differential expression in the medial temporal-lobe system, including hippocampal formation and perirhinal cortex involved in memory storage, and learning and memory defects in the transgenic mice suggest a specialized role for C21orf5 in cognitive processes. These evidences suggest that C21orf5 is an attractive candidate gene contributing to neurological alterations responsible for mental retardation in DS patients.

Animals↗

Physical fitness and adults with mental retardation. An overview of current research and future directions.

The deinstitutionalization movement of the past 25 years has focused on the placement of people with mental retardation into community-based settings. There is a need for exercise- and health-related professionals to demonstrate a thorough understanding of the term mental retardation and all of the intellectual and behavioural ramifications that coexist with this condition before addressing the 'how to' of fitness evaluation. Therefore, the article outlines the range of intellectual and behavioural characteristics of this population, based on the level of retardation. Many researchers investigating body composition have reported that a disproportionate number of adults with mental retardation carry a percentage of body fat that would be considered unhealthy (e.g. it increases the risk of early onset of such diseases as hypertension and adult onset diabetes mellitus). Living arrangements (i.e. institution vs smaller residences) play a role in the prevalence of obesity. Many attempts of researchers to control weight in adults with mental retardation through caloric restriction, exercise, and a combination of diet and exercise, have had a varied outcome. Cardiovascular capacity is considered by most exercise physiologists as the major physiological indicator for overall fitness. The majority of researchers who have evaluated the cardiovascular fitness levels of adults with mental retardation have reported fitness levels representative of a very sedentary population. Therefore, one would expect a keen sense of urgency among researchers to develop training regimens targeted specifically for people with mental retardation. Many have been developed, but to date only 2 cardiovascular training regimens have been reported that specifically describe the necessary components of an exercise programme (i.e. frequency, duration, intensity) that would allow for reproducibility--a stationary bicycle routine using the Schwinn 'Air-Dyne' ergometer and a run/walk programme. Of these, only the programme using the Schwinn 'Air-Dyne' ergometer reported significant improvements in cardiopulmonary fitness. Researchers have demonstrated that: (1) body strength is valuable for recreation activities and activities of daily living; (2) competence in upper body muscular skills is a prerequisite for many available vocational opportunities; and (3) positive correlations have been established between muscular strength and industrial work performance in people with mental retardation. Therefore, there is a need for appropriate evaluation procedures for determining the muscular strength and endurance of people with mental retardation. The future directions for researchers and professionals concerned with the fitness status of people with mental retardation includes answering question such as: What will be the effect of obesity on general health status?(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

Clinical study of the effects of age on the physical health of adults with mental retardation.

Physical disorders and pharmacotherapy for all 134 people with mental retardation ages 65 years and over living in Leicestershire, United Kingdom, were examined. Results were compared with a randomly selected group of 73 younger adults with mental retardation. Group comparisons revealed higher rates of urinary incontinence, immobility, hearing impairments, arthritis, hypertension, and cerebrovascular disease among the older group. The younger group had higher rates of dermatological disorders; congenital heart disease; ear, nose, and throat (ENT) disorders; and neurological disorders (excluding Parkinson disease). The older group took more drugs for physical illness. The effect of ageing on physical morbidity outweighs the effect of people with more severe mental retardation dying younger: Older people with mental retardation have significant physical health needs.

Activities of Daily Living↗

Low dose intradermal vaccination against hepatitis B in mentally retarded patients.

Ninety-two patients and 28 staff members of an institute for mentally retarded patients were immunized intradermally with 2 microgram doses hepatitis B vaccine (HB-Vax), initially at month 0 and 1, and after evaluation followed by two booster injections at month 5 and 10, respectively. Blood samples were taken at months 2 and 11. Seroconversion rates of the two groups were similar on both occasions. Titre distributions for mentally retarded patients and staff members corrected for age, side effects and sex using multiple regression were significantly different at month 2 (p = 0.05) but not at month 11. Geometric mean titres for mentally retarded patients and staff members were 39 and 67 at month 2, respectively, and 1082 and 672 IU l-1 at month 11, respectively. Percentage anti-HBs/a(w) differed significantly between patients and staff members. Side effects, largely local (pigmentation), were observed with a frequency of about 35% in both mentally retarded patients and staff members. Since 92% of the mentally retarded patients had anti-HBs titres greater than 10 IU l-1 and approximately equal to 80% greater than 100 IU l-1, low dose vaccination, four injections by intradermal route, seems to be a suitable cost-reducing immunization system in institutes for mentally retarded patients.

Female↗

MECP2 mutations or polymorphisms in mentally retarded boys: diagnostic implications.

BACKGROUND: Among the well characterized X-linked conditions causing mental retardation, mutations in the methyl-CpG-binding protein 2 gene (MECP2) in Xq28 have been found in up to 85% of patients with Rett syndrome, a neurologic disorder which, in addition to other symptoms, severely affects higher cognitive functions in females. Mutations in the MECP2 gene are involved in a broad spectrum of phenotypes from classical Rett syndrome to mild intellectual difficulties in females and neonatal encephalopathy in males. Recently, mutations in the MECP2 gene were reported in males with non-specific mental retardation suggesting that defects in MECP2 could be responsible for up to 2% of X-linked mental retardation. METHODS: We screened by denaturing high-pressure liquid chromatography the entire coding region and flanking intronic sequences of the MECP2 gene in a cohort of 354 mentally retarded males found negative for an expansion across the FRAXA CGG repeat and in a family in which a boy and his sister were mentally retarded. RESULTS: We identified mainly silent polymorphisms within the MECP2 gene, together with four sequence alterations of unknown significance, i.e. three missense mutations (T197M, T228S, and P376S) and one substitution at position -19 in intron 3 (378-19delT). Further familial investigations allowed us to ruled out a pathogenic effect for the intronic variant, the T228S and the P376S missense mutations. CONCLUSIONS: These results confirm that MECP2 mutations in males are far more rare than initially thought and call for a careful evaluation of the pathogenicity of the MECP2 missense mutations identified in mentally retarded males before genetic counseling is proposed to the relatives.

Chromatography, High Pressure Liquid↗

Screening with the FMR1 protein test among mentally retarded males.

The fragile X syndrome is characterized by X-linked mental retardation with additional features such as a long face with large protruding ears, macroorchidism, and eye-gaze avoidance. The disorder is caused by an abnormally expanded CGG repeat within the first exon of the fragile X mental retardation (FMR1) gene that is associated with shutdown of transcription and absence of the fragile X mental retardation protein (FMRP). Detection of patients and carriers of the fragile X syndrome is done by DNA analysis of the CGG repeat, whereas the FMRP antibody test allows rapid detection of male patients using bloodsmears. In a screening program for the fragile X syndrome in the southwest of the Netherlands, 412 males with mental retardation of unknown cause were subjected to the protein test. The patients were scored for fragile X features and their DNA tested for the FMR1 mutation, as reported previously. The FMRP test detected two fragile X patients with a repeat expansion in FMR1, whereas normal protein expression was observed in all the retarded male patients with a normal repeat. The FMRP test was found to be suitable for screening among a large population of retarded males. The results also suggest that mutations other than the CGG repeat leading to absence of detectable FMRP are apparently rare among mentally retarded males.

Antibodies↗

The differential validity of hyperactivity/attention deficits and conduct problems among mentally retarded children.

The independence of hyperactivity, attention deficits, and conduct problems among mentally retarded children was addressed using factors of the Conners' Teacher Rating Scale-39 (CTRS-39) and the more recently developed IOWA Conners' inattention/overactivity (IO) and aggression (A) subscales. CTRS-39 ratings were obtained for children of normal intelligence and for mentally retarded children. Differences between the groups were examined as were intercorrelations of the Conners' factors and IOWA subscales. Conduct problems proved to be less strongly associated with hyperactivity and attention deficits among mentally retarded children compared to children of normal intelligence. However, attention problems and conduct problems may be associated with mental retardation in general. Implications of these data and CTRS scoring system recommendations for mentally retarded children are discussed.

Aggression↗

Self-reported fears in children with and without mental retardation.

The frequency, intensity, and content of specific fears in 299 children with and without mental retardation (ages 6 to 13 years) were investigated. The children with mental retardation reported a greater fear intensity than did younger children without mental retardation but did not differ in the number of fears reported. However, children with mental retardation reported both a greater frequency and intensity of fears than did similar-age peers without mental retardation. Gender differences in frequency and intensity of fears were assessed, and the most common fears (with and without regard to intensity ratings) of the groups were compared and implications for future research and practice presented.

Adolescent↗

Dynamic contextual variables and the directives of persons with mental retardation.

We examined the ability of 14 persons with mental retardation and of 14 children without mental retardation to adjust the linguistic form of their directives as a function of their listener's affective state (happy or sad) and activity level (busy or idle). Directives were elicited by requiring the subjects to obtain toys from an adult listener. We found that both groups of subjects were sensitive to these dimensions of the communicative context. However, the directive forms used by the subjects with mental retardation were more imposing overall.

Adolescent↗

Recognition of emotion by mentally retarded adolescents and young adults.

Mentally retarded adolescents and young adults, together with nonretarded children individually matched for verbal mental age, were given tasks in which they chose photographs of faces to accompany emotionally expressive voices and photographs of nonemotional things or events to accompany recorded sounds. Retarded individuals performed less well than did nonretarded control subjects on the emotion tasks but were not so impaired on the nonemotion tasks. These results suggest that mentally retarded individuals may have specific deficits in recognizing how bodily expressions of emotion are coordinated with each other.

Adolescent↗

Dignity or denial? Decisions regarding initiation of dialysis and medical therapy in the institutionalized severely mentally retarded.

Decisions regarding health care of the severely mentally retarded can be difficult. We present 2 cases of patients with severe mental retardation who lived in long-term care facilities. Both patients had progressive loss of renal function and eventually reached end-stage renal disease. In each case, the decision was made not to initiate dialysis. We discuss issues of dialysis and medical care of the severely mentally retarded and advocate using the principles of "best respect" and "best interest" in making medical decisions in this population.

Adult↗

Community mental health and mental retardation services in the United States: a comparative study of resource allocation.

OBJECTIVE: Preliminary studies suggest that during the 1980s, spending for community mental retardation services in the United States may have grown much more rapidly than spending for community mental health. The primary objective of this study was to test empirically the validity of this thesis on a national basis. An additional objective was to determine why such a distinction in community spending patterns might have evolved nationally. METHOD: The study used states as the units of analysis and employed a five-factor hierarchical regression to predict variance in mental health and mental retardation spending. Factors were state size, state wealth, degree of federal assistance, state civil rights activity, and strength of consumer advocacy groups. Strong roles for the civil rights and consumer advocacy factors were hypothesized. A collateral opinion survey in the 10 states exhibiting the greatest within-state difference in community mental health and mental retardation spending was also completed. RESULTS: Community mental retardation spending grew nearly four times more rapidly than community mental health spending in the 1980s. The consumer advocacy and civil rights factors were strongly associated with spending for community mental retardation services in the states, but these factors did not predict spending for community mental health services. CONCLUSIONS: Study recommendations included strengthening mental health family and consumer advocacy groups in the states and promoting systematic exchange between the mental health and mental retardation fields through joint state planning initiatives, studies, and conferences. The need for Medicaid reform is a unifying theme in both the mental health and mental retardation fields.

Community Mental Health Services↗

Kissing complex RNAs mediate interaction between the Fragile-X mental retardation protein KH2 domain and brain polyribosomes.

Fragile-X mental retardation is caused by loss of function of a single gene encoding the Fragile-X mental retardation protein, FMRP, an RNA-binding protein that harbors two KH-type and one RGG-type RNA-binding domains. Previous studies identified intramolecular G-quartet RNAs as high-affinity targets for the RGG box, but the relationship of RNA binding to FMRP function and mental retardation remains unclear. One severely affected patient harbors a missense mutation (I304N) within the second KH domain (KH2), and some evidence suggests this domain may be involved in the proposed role of FMRP in translational regulation. We now identify the RNA target for the KH2 domain as a sequence-specific element within a complex tertiary structure termed the FMRP kissing complex. We demonstrate that the association of FMRP with brain polyribosomes is abrogated by competition with the FMRP kissing complex RNA, but not by high-affinity G-quartet RNAs. We conclude that mental retardation associated with the I304N mutation, and likely the Fragile-X syndrome more generally, may relate to a crucial role for RNAs harboring the kissing complex motif as targets for FMRP translational regulation.

Amino Acid Motifs↗

Referential first mention in narratives by mildly mentally retarded adults.

Referential first mentions in narrative reports of a short film by 40 mildly mentally retarded adults and 20 nonretarded adults were compared. The mentally retarded sample included equal numbers of male and female, and black and white speakers. The mentally retarded speakers made significantly fewer first mentions and significantly more errors in the form of the first mentions than did nonretarded speakers. A pattern of better performance by black males than by other mentally retarded speakers was found. It is suggested that task difficulty and incomplete mastery of the use of definite and indefinite forms for encoding old and new information, rather than some global type of egocentrism, accounted for the poorer performance by mentally retarded speakers.

Adult↗

Application of a Rasch analysis to the examination of the perception of facial affect among persons with mental retardation.

An instrument for the assessment of perception of nonverbal facial affect was developed and administered to two separate groups of respondents: adults with mental retardation and adults without mental retardation. The instrument was developed and calibrated using an item response theory (Rasch) analysis on respondents without mental retardation. Following assurance of item stability, data were analyzed using an anchored analysis for persons without mental retardation. Cumulative score differences between the two groups were expected and were found. The Rasch analysis uncovered a difference in the structure of the latent trait of understanding of facial affect between the two groups. In view of these qualitative differences, the argument is presented that quantitative differences in the two groups are irrelevant. We suggest that qualitative differences such as those found herein may partially account for the traditionally limited scope of generalization and maintenance of treatment effects of social skills training with persons with mental retardation. Theoretical and empirical implications of the findings, and future research directions based on these qualitative differences are discussed.

Activities of Daily Living↗