Interstitial Deletions at 6q14.1-q15 Associated with Obesity, Developmental Delay and a Distinct Clinical Phenotype

BACKGROUND: Interstitial deletions of the long arm of chromosome 6 have been described in several patients with obesity and a Prader-Willi-like phenotype. Haploinsufficiency of the SIM1 gene located at 6q16.3 is suggested as being responsible for the regulation of body weight. Here we report on 2 patients with interstitial deletions at 6q14.1-q15 presenting with obesity and symptoms strikingly similar to those reported for deletions involving the SIM1 gene despite not having a deletion of this gene. METHODS: Array comparative genomic hybridisation was used to diagnose 2 children with obesity and developmental delay, revealing 2 interstitial deletions at 6q14.1-q15 of 8.73 and 4.50 Mb, respectively, and a region of overlap of 4.2-Mb. RESULTS: The similar phenotype in the 2 patients was most likely due to a 4.2-Mb common microdeletion at 6q14.1-q15. Another patient has previously been described with an overlapping deletion. The 3 patients share several features, such as developmental delay, obesity, hernia, rounded face with full cheeks, epicanthal folds, short palpebral fissures, bulbous nose, large ears, and syndactyly between toes II and III. CONCLUSIONS: Together with a previously reported patient, our study suggests that the detected deletions may represent a novel clinically recognisable microdeletion syndrome caused by haploinsufficiency of dosage-sensitive genes in the 6q14.1-q15 region.

Measurement of the influence of the physical environment on adverse health outcomes: technical report from the Canadian Study of Health and Aging

A paucity of information exists to characterize the relationship between the health status of elderly people and their physical environment. The Canadian Study of Health and Aging (CSHA) is a multicenter study of the distribution of dementia among community-dwelling and institutionalized Canadians aged 65 years and older. The study also provides the opportunity to examine issues such as the physical environment which may be related to the health of elderly people. Six items were used to assess the cleanliness, neatness, and maintenance of the inside and outside of the homes of 8,134 community-dwelling individuals. Data were also obtained to evaluate cognition, physical health, and functional capacity. Five years after the original survey, information pertaining to subsequent institutionalization and/or mortality was obtained. A significant relationship was found between classification of physical environment and the outcomes of institutionalization and mortality. The likelihood of both adverse outcomes was notably higher for individuals living in a "less than ideally maintained environment" compared to an "ideally maintained environment." Limitations of the six items used to assess the physical environment and ways in which to improve the sensitivity of the items, consequently avoiding measurement bias, are discussed.

Reliability and validity of questions about exercise in the Canadian Study of Health and Aging

Regular exercise in elderly people has beneficial health effects. We examined exercise frequency and intensity from the Canadian Study of Health and Aging Risk Factor Questionnaire (RFQ). The reliability and validity of these two questions individually, and when combined to form a scale, are reported. Agreement between the self-administered RFQ and an interviewer-administered Add-on Study was examined using intraclass correlations, which were 0.80 for frequency (95% CI 0.77-0.82, p < .001) and 0.75 for intensity (95% CI 0.71-0.78, p = .012). Individuals reporting high levels of exercise frequency, intensity, and a combination of the two showed a smaller proportion of adverse health markers than those reporting no regular exercise. Predictive validity assessed by Cox proportional hazards modeling of mortality showed that the high and moderate levels of frequency, intensity, and combined exercise groups differed significantly (all p < .001) from the no exercise group. We have found that these exercise questions, though simple, appear reliable and valid. The finding that even comparatively crude exercise questions can demonstrate an important relationship to death suggests that the signal for exercise is a strong one, and future studies should seek to better examine mechanisms by which exercise benefit is conferred.

Progression of impairment in patients with vascular cognitive impairment without dementia

Little is known about progression, short of dementia, in vascular cognitive impairment. In the Canadian Study of Health and Aging, 149 participants (79.3 +/- 6.7 years; 61% women) were found to have vascular cognitive impairment, no dementia (CIND). After 5 years, 77 participants (52%) had died and 58 (46%) had developed dementia. Women were at greater risk of dementia (OR 2.1, 1.0 to 4.5). Of 32 participants alive without dementia, cognition had deteriorated in seven and improved in four. Half of those with vascular CIND developed dementia within 5 years, suggesting a target for preventive interventions.

Inter-rater reliability of the diagnosis of vascular cognitive impairment at a memory clinic

Consensus criteria for the diagnosis of vascular dementia (VaD) are gradually being replaced with data-based criteria. We report the inter-rater reliability of a new set of empirically-derived criteria for vascular cognitive impairment (VCI). Stratified sampling, with optimal allocation, was employed to randomly select 36 patients from the Queen Elizabeth II Health Science Centre's Memory Disability Clinic. Chart reviews were conducted independently by 4 physicians. Each physician classified the patients as having either: no cognitive impairment, VCI or Alzheimer's disease (AD). VCI was further classified both clinically (VCI without dementia, VaD or AD with a vascular component) and radiographically (infarcts, white matter changes, single strategic stroke). The intraclass correlation coefficient (ICC) for the diagnosis by physicians of VCI or otherwise was based on a repeated-measures analysis of variance with raters as the independent variable. A significant coefficient of reliability (average ICC = 0.88, 95% CI = 0.80-0.93) was obtained (H(o): rho </= 0.80, p = 0.03). Where differences in diagnosis occurred, the discrepancies most commonly resulted within the subtypes of VCI (9 cases) or between the diagnoses of AD and VCI (9 cases). Instances of diagnostic incongruity were typically due to the disagreement of a single rater (10 cases). This study demonstrates a high degree of reliability of criteria for VCI by physicians in a memory clinic, and can also be understood as an aspect of construct validation of those criteria. In the absence of a readily available biological marker for VCI, clinical criteria are necessary and can be reliably employed.

The diagnosis of "mixed" dementia in the Consortium for the Investigation of Vascular Impairment of Cognition (CIVIC)

If vascular risk factors are risk for Alzheimer's disease (AD), and if "pure" vascular dementia (VaD) is less common than has been thought, what do we make of the diagnosis of mixed dementia? We report characteristics of those with mixed dementia in a prospective, seven center, clinic-based Canadian study. Of 1,008 patients, 372 were diagnosed with AD, 149 with vascular cognitive impairment (VCI) including 76 with mixed AD/VaD, and 82 with other types of dementia. The mean age of patients with mixed AD/VaD was 78.0 +/- 7.6 years; 49% were female. These proportions differed significantly between dementia diagnosis subgroup (p < 0.001) showing a trend which is evident in all comparisons--AD/VaD patients fall in between AD and VaD. Vascular risk factors were present significantly more often in mixed AD/VaD than in AD (p < 0.001). More mixed AD/VaD (20%) than AD patients (4%) had focal signs, compared with 38% of those with vascular dementia and 12% with other types of dementia. Between the initial clinical diagnosis and the final diagnosis (which utilized neuroimaging and neuropsychological data) AD/VaD was the least stable diagnosis. Neuroimaging of ischemic lesions was the most common reason for reassignment from AD to the mixed AD/VaD diagnosis (17 cases). These data suggest that an operational definition of mixed AD/VaD can be proposed on presentation and clinical/radiographic findings, but indifferent to vascular risk factors. The concept of mixed dementia should be extended to include vascular dementia in combination with dementias, other than Alzheimer's disease.

Prevalence and outcomes of vascular cognitive impairment. Vascular Cognitive Impairment Investigators of the Canadian Study of Health and Aging

OBJECTIVE

To assess the importance of vascular cognitive impairment and its three subgroups (cognitive impairment, no dementia; vascular dementia; and AD with a vascular component) to the prevalence and burden of cognitive impairment in elderly people.

BACKGROUND

Vascular lesions may produce a spectrum of cognitive changes. Omitting elderly patients whose cognitive impairment falls short of dementia (vascular cognitive impairment, no dementia) may give a falsely low indication of the prevalence and burden of disease. To test this proposition, we compared the rates of adverse outcomes for patients with no cognitive impairment, vascular cognitive impairment (and its subgroups), and probable AD.

METHODS

The Canadian Study of Health and Aging is a prospective cohort study of 10,253 randomly selected community-dwelling and institution-dwelling respondents aged 65 years or older. In the community, all participants (n = 9,008) were screened for cognitive impairment; those who screened positive and a sample of those who screened negative received a clinical assessment (n = 1,659). All patients living in institutions received a clinical assessment (n = 1,255). Participants were reassessed 5 years after the original survey.

RESULTS

Vascular cognitive impairment without dementia was the most prevalent form of vascular cognitive impairment among those aged 65 to 84 years. Rates of institutionalization and mortality for those with vascular cognitive impairment were significantly higher than those of people who had no cognitive impairment, and the mortality rate for patients with vascular cognitive impairment was similar to that of patients with AD.

CONCLUSIONS

Failure to consider vascular cognitive impairment without dementia underestimates the prevalence of impairment and the risk for adverse outcomes associated with vascular cognitive impairment.

Pathogenesis of diabetes-induced congenital malformations

The increased rate of fetal malformation in diabetic pregnancy represents both a clinical problem and a research challenge. In recent years, experimental and clinical studies have given insight into the teratological mechanisms and generated suggestions for improved future treatment regimens. The teratological role of disturbances in the metabolism of inositol, prostaglandins, and reactive oxygen species has been particularly highlighted, and the beneficial effect of dietary addition of inositol, arachidonic acid and antioxidants has been elucidated in experimental work. Changes in gene expression and induction of apoptosis in embryos exposed to a diabetic environment have been investigated and assigned roles in the teratogenic processes. The diabetic environment appears to simultaneously induce alterations in several interrelated teratological pathways. The complex pathogenesis of diabetic embryopathy has started to unravel, and future research efforts will utilize both clinical intervention studies and experimental work that aim to characterize the human applicability and the cell biological components of the discovered teratological mechanisms.