Age and pattern of intellectual decline among Down Syndrome and other mentally retarded adults

Gibson, David; Groeneweg, Gerrit; Paul, Jerry; Harris, Andrew T.

doi:10.1097/00004356-198803000-00006

Cited by 33 publications

(28 citation statements)

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“…By contrast, the performance of TD individuals begins to decline in the early adult years. In addition, cross-sectional results of Gibson, Groeneweg, Jerry, and Harris (1988) suggested that individuals with DS decline rapidly in Wechsler Block Design performance during the 4 th decade, which was not the case for individuals with ID (see also Jozsvai, Kartakis, & Collings, 2002). …”

Section: Resultsmentioning

confidence: 99%

Visuo-spatial ability in individuals with Down syndrome: Is it really a strength?

Yang

Conners

Merrill

2014

Research in Developmental Disabilities

107

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Down syndrome (DS) is associated with extreme difficulty in verbal skills and relatively better visuo-spatial skills. Indeed, visuo-spatial ability is often considered a strength in DS. However, it is not clear whether this strength is only relative to the poor verbal skills, or, more impressively, relative to cognitive ability in general. To answer this question, we conducted an extensive literature review of studies on visuo-spatial abilities in people with Down syndrome from January 1987 to May 2013. Based on a general taxonomy of spatial abilities patterned after Lohman, Pellegrino, Alderton, and Regian (1987) and Carroll (1993) and existing studies of DS, we included five different domains of spatial abilities – visuo-spatial memory, visuo-spatial construction, mental rotation, closure, and wayfinding. We evaluated a total of 49 studies including 127 different comparisons. Most comparisons involved a group with DS vs. a group with typical development matched on mental age and compared on a task measuring one of the five visuo-spatial abilities. Although further research is needed for firm conclusions on some visuo-spatial abilities, there was no evidence that visuo-spatial ability is a strength in DS relative to general cognitive ability. Rather, the review suggests an uneven profile of visuo-spatial abilities in DS in which some abilities are commensurate with general cognitive ability level, and others are below.

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Section: Resultsmentioning

confidence: 99%

Visuo-spatial ability in individuals with Down syndrome: Is it really a strength?

Yang

Conners

Merrill

2014

Research in Developmental Disabilities

107

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“…In DS patients, mental retardation is highly diverse in terms of the severity of the cognitive disability as well as the manifestation of additional (noncognitive) symptoms. IQ in people with DS is usually in the severely to moderately retarded range (IQ ϭ 25-55) (133,313,370). IQ in DS is not constant across the life (35), but it progressively decreases with age (273,370), although this scenario has changed in the last years thanks to the early intervention programs and the social integration of these persons (284).…”

Section: A Neurocognitive Profile In Down Syndromementioning

confidence: 99%

Aneuploidy: From a Physiological Mechanism of Variance to Down Syndrome

Dierssen¹,

Hérault²,

Estivill³

2009

Physiological Reviews

124

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Quantitative differences in gene expression emerge as a significant source of variation in natural populations, representing an important substrate for evolution and accounting for a considerable fraction of phenotypic diversity. However, perturbation of gene expression is also the main factor in determining the molecular pathogenesis of numerous aneuploid disorders. In this review, we focus on Down syndrome (DS) as the prototype of "genomic disorder" induced by copy number change. The understanding of the pathogenicity of the extra genomic material in trisomy 21 has accelerated in the last years due to the recent advances in genome sequencing, comparative genome analysis, functional genome exploration, and the use of model organisms. We present recent data on the role of genome-altering processes in the generation of diversity in DS neural phenotypes focusing on the impact of trisomy on brain structure and mental retardation and on biological pathways and cell types in target brain regions (including prefrontal cortex, hippocampus, cerebellum, and basal ganglia). We also review the potential that genetically engineered mouse models of DS bring into the understanding of the molecular biology of human learning disorders.

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“…This condition is a paradigm of human aneuploid disorders with supernumerary copies of a chromosome and could be considered as a prototype of the ‘disorders of the genome’. DS represents one-third of the cases of mental retardation and cognitive impairment in school-aged children (2–4) and is associated with a large panel of dysmorphologies, such as a characteristic facies, skeletal anomalies and brain alterations at the level of the prefrontal cortex, the hippocampus and the cerebellum. DS clinical features also include developmental delay, metabolic defects and other symptoms and associated diseases, but their overall expressivity and penetrance are highly variable.…”

Section: Introductionmentioning

confidence: 99%

A new mouse model for the trisomy of the Abcg1–U2af1 region reveals the complexity of the combinatorial genetic code of down syndrome

Pereira

Magnol

Sahún

et al. 2009

Human Molecular Genetics

106

129

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Mental retardation in Down syndrome (DS), the most frequent trisomy in humans, varies from moderate to severe. Several studies both in human and based on mouse models identified some regions of human chromosome 21 (Hsa21) as linked to cognitive deficits. However, other intervals such as the telomeric region of Hsa21 may contribute to the DS phenotype but their role has not yet been investigated in detail. Here we show that the trisomy of the 12 genes, found in the 0.59 Mb (Abcg1–U2af1) Hsa21 sub-telomeric region, in mice (Ts1Yah) produced defects in novel object recognition, open-field and Y-maze tests, similar to other DS models, but induces an improvement of the hippocampal-dependent spatial memory in the Morris water maze along with enhanced and longer lasting long-term potentiation in vivo in the hippocampus. Overall, we demonstrate the contribution of the Abcg1–U2af1 genetic region to cognitive defect in working and short-term recognition memory in DS models. Increase in copy number of the Abcg1–U2af1 interval leads to an unexpected gain of cognitive function in spatial learning. Expression analysis pinpoints several genes, such as Ndufv3, Wdr4, Pknox1 and Cbs, as candidates whose overexpression in the hippocampus might facilitate learning and memory in Ts1Yah mice. Our work unravels the complexity of combinatorial genetic code modulating different aspect of mental retardation in DS patients. It establishes definitely the contribution of the Abcg1–U2af1 orthologous region to the DS etiology and suggests new modulatory pathways for learning and memory.

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Age and pattern of intellectual decline among Down Syndrome and other mentally retarded adults

Cited by 33 publications

References 0 publications

Visuo-spatial ability in individuals with Down syndrome: Is it really a strength?

Visuo-spatial ability in individuals with Down syndrome: Is it really a strength?

Aneuploidy: From a Physiological Mechanism of Variance to Down Syndrome

A new mouse model for the trisomy of the Abcg1–U2af1 region reveals the complexity of the combinatorial genetic code of down syndrome

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