Raimo Sulkava

A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD

The chromosome 9p21 amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD) locus contains one of the last major unidentified autosomal-dominant genes underlying these common neurodegenerative diseases. We have previously shown that a founder haplotype, covering the MOBKL2b, IFNK, and C9ORF72 genes, is present in the majority of cases linked to this region. Here we show that there is a large hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 on the affected haplotype. This repeat expansion segregates perfectly with disease in the Finnish population, underlying 46.0% of familial ALS and 21.1% of sporadic ALS in that population. Taken together with the D90A SOD1 mutation, 87% of familial ALS in Finland is now explained by a simple monogenic cause. The repeat expansion is also present in one-third of familial ALS cases of outbred European descent, making it the most common genetic cause of these fatal neurodegenerative diseases identified to date.

Serum Total Cholesterol, Apolipoprotein E {FC12}e4 Allele, and Alzheimer’s Disease

The σ4 allele of the apolipoprotein E (apoE) is associated with Alzheimer’s disease (AD) and also with elevated serum total cholesterol and low-density lipoprotein levels. However, the interrelationships between apoE genotype, plasma cholesterol levels and AD risk have been studied very little. We examined the possible role of serum total cholesterol in the pathogenesis of AD in a population-based sample of 444 men, aged 70–89 years, who were survivors of the Finnish cohorts of the Seven Countries Study. Previous high serum cholesterol level (mean level ≥6.5 mmol/l) was a significant predictor of the prevalence of AD (odds ratio = 3.1; 95% confidence interval = 1.2, 8.5) after controlling for age and the presence of apoE σ4 allele. In men who subsequently developed AD the cholesterol level decreased before the clinical manifestations of AD. We conclude that high serum total cholesterol may be an independent risk factor for AD and some of the effect of the apoE σ4 allele on risk of AD might be mediated through high serum cholesterol.

Apolipoprotein E, Dementia, and Cortical Deposition of β-Amyloid Protein

BACKGROUND The epsilon 4 allele of apolipoprotein E has been associated with an increased risk of late-onset Alzheimers disease. In a cohort of elderly subjects we prospectively investigated the relation between the apolipoprotein E genotype, dementia, and the accumulation of beta-amyloid protein in the cerebral cortex. METHODS Autopsy involving neuropathological analysis and DNA analysis of frozen blood samples were performed in 92 of 271 persons who were at least 85 years of age, who had been living in Vantaa, Finland, on April 1, 1991, and who had died between that time and the end of 1993. All subjects had been tested for dementia. Apolipoprotein E genotyping was done with a solid-phase minisequencing technique. The percentage of the cortex occupied by methenamine silver-stained plaques was used as an estimate of the extent of beta-amyloid protein deposition. RESULTS The frequency of the epsilon 4 allele was significantly higher in the subjects with Alzheimers disease than in the subjects without dementia (30 percent vs. 8 percent, P < 0.001). There was a greater accumulation of beta-amyloid protein in the brain and more neurofibrillary tangles in the subjects with the epsilon 4 allele than in those without it (P < 0.001). The deposition of beta-amyloid protein varied according to the genotype in both the subjects with dementia and those without dementia: it was lowest in those with the epsilon 2/epsilon 3 genotype, intermediate in those with the epsilon 3/epsilon 3 genotype, and highest in those with the epsilon 3/epsilon 4 genotype. A single subject had the epsilon 4/epsilon 4 genotype and had dementia. CONCLUSIONS The epsilon 4 allele of apolipoprotein E is significantly associated with Alzheimers disease. Even in elderly subjects without dementia, the apolipoprotein E genotype is related to the degree of deposition of beta-amyloid protein in the cerebral cortex.

White Matter Hyperintensities on MRI in the Neurologically Nondiseased Elderly: Analysis of Cohorts of Consecutive Subjects Aged 55 to 85 Years Living at Home

BACKGROUND AND PURPOSE We undertook this study to evaluate the frequency and risk factors of white matter hyperintensities seen on T2-weighted MR imaging. We examined cohorts of neurologically nondiseased elderly subjects participating in a general-community study, the Helsinki (Finland) Aging Brain Study. Cohorts of consecutive subjects aged 55, 60, 65, 70, 75, 80, and 85 years (n = 20, 18, 20, 18, 19, 18, and 15, respectively; total, n = 128) were divided into a young-old (age < 75 years, n = 76) group and an old-old (age > or = 75 years, n = 52) group. METHODS Frequency of hyperintensities seen on T2-weighted axial and coronal MR images (0.02 T) was rated using a four-point scale in periventricular and centrum semiovale areas. RESULTS The majority of the subjects showed only mild white matter hyperintensities, which were more frequent in the periventricular areas. Age was the most important factor to explain the presence of hyperintensities. A logistic regression analysis related periventricular hyperintensities in the entire group to central atrophy (odds ratio [OR], 4.7; 95% confidence interval [CI], 1.7 to 12.9) and silent infarcts (OR, 5.6; 95% CI, 1.0 to 19.8); among the young-old, hyperintensities related to diabetes (OR, 17.0; 95% CI, 1.9 to 154.2) and central atrophy (OR, 14.7; 95% CI, 3.5 to 61.8). Centrum semiovale hyperintensities related in the entire group to cardiac arrhythmia (OR, 4.0; 95% CI, 1.0 to 15.5), central atrophy (OR, 3.9; 95% CI, 1.2 to 12.4), and silent infarcts (OR, 3.6; 95% CI, 1.0 to 12.5). CONCLUSIONS These mild white matter hyperintensities in the neurologically nondiseased elderly related especially to age and also to concomitant silent infarcts, atrophy, and some vascular risk factors. The known factors, however, explained only part of the variation. The young-old and old-old groups showed different associations. In contrast to former assumptions, the presence of white matter hyperintensities among the aged is likely to be linked to other as yet unidentified age-related factors.

Randomised, clinically controlled trial of intensive geriatric rehabilitation in patients with hip fracture: subgroup analysis of patients with dementia

Abstract Objective: To evaluate the effect of intensive geriatric rehabilitation on demented patients with hip fracture. Design: Preplanned subanalysis of randomised intervention study. Settting: Jyväskylä Central Hospital, Finland. Participants: 243 independently living patients aged 65 years or older admitted to hospital with hip fracture. Intervention: After surgery patients in the intervention group (n=120) were referred to the geriatric ward whereas those in the control group were discharged to local hospitals. Main outcome measures: Length of hospital stay, mortality, and place of residence three months and one year after surgery for hip fracture. Results: The median length of hospital stay of hip fracture patients with moderate dementia (mini mental state examination score 12-17) was 47 days in the intervention group (n=24) and 147 days in the control group (n=12, P=0.04). The corresponding figures for patients with mild dementia (score 18-23) were 29 days in the intervention group (n=35) and 46.5 days in the control group (n=42, P=0.002). Three months after the operation, in the intervention group 91% (32) of the patients with mild dementia and 63% (15) of the patients with moderate dementia were living independently. In the control group, the corresponding figures were 67% (28) and 17% (2). There were no significant differences in mortality or in the lengths of hospital stay of severely demented patients and patients with normal mini mental state examination scores. Conclusions: Hip fracture patients with mild or moderate dementia can often return to the community if they are provided with active geriatric rehabilitation.

Prevalence of severe dementia in Finland

A sample of 8,000 subjects to represent the population of Finland aged 30 years and over was used to identify patients with severe dementia; 141 cases were found. The prevalence of all types of severe dementia was 1.8% in the whole study population and 6.7% in the population aged 65 years and over. The prevalence increased with advancing age to 17.3% in the age group 85 years and over. Primary degenerative dementia constituted 50% of all cases; multi-infarct and combined dementia, 39%; and secondary dementia, 11%. Fifty-seven percent of the patients lived in institutions.

Chromosome 9p21 in amyotrophic lateral sclerosis in Finland: a genome-wide association study

BACKGROUND The genetic cause of amyotrophic lateral sclerosis (ALS) is not well understood. Finland is a well suited location for a genome-wide association study of ALS because the incidence of the disease is one of the highest in the world, and because the genetic homogeneity of the Finnish population enhances the ability to detect risk loci. We aimed to identify genetic risk factors for ALS in the Finnish population. METHODS We did a genome-wide association study of Finnish patients with ALS and control individuals by use of Illumina genome-wide genotyping arrays. DNA was collected from patients who attended an ALS specialty clinic that receives referrals from neurologists throughout Finland. Control samples were from a population-based study of elderly Finnish individuals. Patients known to carry D90A alleles of the SOD1 gene (n=40) were included in the final analysis as positive controls to assess whether our genome-wide association study was able to detect an association signal at this locus. FINDINGS We obtained samples from 442 patients with ALS and 521 control individuals. After quality control filters were applied, 318 167 single nucleotide polymorphisms (SNPs) from 405 people with ALS and 497 control individuals were available for analysis. We identified two association peaks that exceeded genome-wide significance. One was located on chromosome 21q22 (rs13048019, p=2·58×10(-8)), which corresponds to the autosomal recessive D90A allele of the SOD1 gene. The other was detected in a 232 kb block of linkage disequilibrium (rs3849942, p=9·11×10(-11)) in a region of chromosome 9p that was previously identified in linkage studies of families with ALS. Within this region, we defined a 42-SNP haplotype that was associated with significantly increased risk of ALS (p=7·47×10(-33) when people with familial ALS were compared with controls, odds ratio 21·0, 95% CI 11·2-39·1) and which overlapped with an association locus recently reported for frontotemporal dementia. For the 93 patients with familial ALS, the population attributable risk for the chromosome 9p21 locus was 37·9% (95% CI 27·7-48·1) and that for D90A homozygosity was 25·5% (16·9-34·1). INTERPRETATION The chromosome 9p21 locus is a major cause of familial ALS in the Finnish population. Our data suggest the presence of a founder mutation for chromosome 9p21-linked ALS. Furthermore, the overlap with the risk haplotype recently reported for frontotemporal dementia provides further evidence of a shared genetic cause for these two neurodegenerative diseases. FUNDING National Institutes of Health and National Institute on Aging, Microsoft Research, ALS Association, Helsinki University Central Hospital, Finnish Academy, Finnish Medical Society Duodecim, and Kuopio University.

Delirium is a strong risk factor for dementia in the oldest-old: a population-based cohort study.

Recent studies suggest that delirium is associated with risk of dementia and also acceleration of decline in existing dementia. However, previous studies may have been confounded by incomplete ascertainment of cognitive status at baseline. Herein, we used a true population sample to determine if delirium is a risk factor for incident dementia and cognitive decline. We also examined the effect of delirium at the pathological level by determining associations between dementia and neuropathological markers of dementia in patients with and without a history of delirium. The Vantaa 85+ study examined 553 individuals (92% of those eligible) aged ≥85 years at baseline, 3, 5, 8 and 10 years. Brain autopsy was performed in 52%. Fixed and random-effects regression models were used to assess associations between (i) delirium and incident dementia and (ii) decline in Mini-Mental State Examination scores in the whole group. The relationship between dementia and common neuropathological markers (Alzheimer-type, infarcts and Lewy-body) was modelled, stratified by history of delirium. Delirium increased the risk of incident dementia (odds ratio 8.7, 95% confidence interval 2.1–35). Delirium was also associated with worsening dementia severity (odds ratio 3.1, 95% confidence interval 1.5–6.3) as well as deterioration in global function score (odds ratio 2.8, 95% confidence interval 1.4–5.5). In the whole study population, delirium was associated with loss of 1.0 more Mini-Mental State Examination points per year (95% confidence interval 0.11–1.89) than those with no history of delirium. In individuals with dementia and no history of delirium (n = 232), all pathologies were significantly associated with dementia. However, in individuals with delirium and dementia (n = 58), no relationship between dementia and these markers was found. For example, higher Braak stage was associated with dementia when no history of delirium (odds ratio 2.0, 95% confidence interval 1.1–3.5, P = 0.02), but in those with a history of delirium, there was no significant relationship (odds ratio 1.2, 95% confidence interval 0.2–6.7, P = 0.85). This trend for odds ratios to be closer to unity in the delirium and dementia group was observed for neuritic amyloid, apolipoprotein ε status, presence of infarcts, α-synucleinopathy and neuronal loss in substantia nigra. These findings are the first to demonstrate in a true population study that delirium is a strong risk factor for incident dementia and cognitive decline in the oldest-old. However, in this study, the relationship did not appear to be mediated by classical neuropathologies associated with dementia.

Dementia with Lewy bodies according to the consensus criteria in a general population aged 75 years or older

Objective: To estimate the prevalence of dementia with Lewy bodies (DLB) according to the consensus criteria in a general population aged 75 years or older. Methods: The “Kuopio 75+ study” is a population based health survey focused on the clinical epidemiology of dementia and functional capacity among elderly subjects aged 75 years or older. On 1 January 1998, a random sample of 700 subjects was drawn from a total population born before 1 January 1923, living in the city of Kuopio, northeast Finland (n = 4518). The study subjects underwent a structured interview and clinical examination. Results: 601 elderly subjects (86% of the random sample) were examined. A dementia disorder was diagnosed in 137—a prevalence of 22.8% (95% confidence interval 19.4% to 26.2%). The prevalence of DLB was 5.0% (3.2% to 6.7%), comprising 22% of all demented subjects. Probable DLB was diagnosed in 20 subjects (3.3% (1.9% to 4.8%)), and possible DLB in 10 (1.7% (0.6% to 2.7%)). The prevalence of Alzheimer’s disease was 10.6% (47% of all demented subjects), of vascular dementia, 5.3% (23%), and of other types of dementing disorders, 1.8% (8%). Conclusions: In a general population aged 75 years and older, the prevalence of a disorder fulfilling the diagnostic criteria of DLB is half that of Alzheimer’s disease and the same as for vascular dementia.

Accuracy of the clinical diagnosis of vascular dementia: a prospective clinical and post-mortem neuropathological study.

Brains from a prospective study of demented patients were investigated post mortem. Of the 27 patients with clinical diagnosis of vascular dementia, 23 showed multiple cerebral infarcts but senile plaques and neurofibrillary tangles were absent or in insignificant numbers. This gives an accuracy of 85%, a figure higher than previously documented.