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R Mayeux

Publications and source records attributed to R Mayeux.

At least 37 records · Page 2Linked to original sources
PubMed2001

Screening for PS1 mutations in a referral-based series of AD cases: 21 novel mutations.

BACKGROUND: Mutations in the presenilin-1 gene (PS1) account for a majority of patients with early-onset familial AD. However, the clinical indications and algorithms for genetic testing in dementia are still evolving. METHODS: The entire open reading frame of the PS1 gene was sequenced in a series of 414 consecutive patients referred for diagnostic testing, including 372 patients with AD and 42 asymptomatic persons with a strong family history of AD. RESULTS: Forty-eight independent patients screened had a PS1 mutation including 21 novel mutations. In addition, 3% of subjects (11/413) had a known polymorphism, the Glu318Gly substitution. The majority of the mutations were missense substitutions but there were three insertions and Delta exon 10 mutation. With six exceptions (codons 35, 178, 352, 354, 358, and 365) most of the mutations occurred at residues conserved in the homologous PS2 gene or in PS1 of other species. CONCLUSIONS: Eleven percent of a referral-based series of patients with AD can be explained by coding sequence mutations in the PS1 gene. The high frequency of PS1 mutations in this study indicates that screening for PS1 mutations in AD is likely to be successful, especially when directed at patients with a positive family history with onset before 60 years (90% of those with PS1 mutations were affected by age 60 years). This will also have significance for the secondary identification of at-risk relatives who might be candidates for future prophylactic therapies for AD.

Adult↗
PubMed2001

Elevated plasma amyloid beta-peptide 1-42 and onset of dementia in adults with Down syndrome.

We compared levels of plasma amyloid beta-peptides Abeta1-42 and Abeta1-40 in 108 demented and nondemented adults with Down syndrome (DS) and 64 adults from the general population. Abeta1-42 and Abeta1-40 levels were significantly higher in adults with DS than in controls (P=0.0001). Compared to nondemented adults with DS, Abeta1-42 levels in demented adults with DS were selectively increased by 26% (28.2 pg/ml vs. 22.4 pg/ml, P=0.004). In addition, mean plasma levels of Abeta1-42 were 22% higher in DS cases with the apolipoprotein varepsilon4 allele than in DS subjects without an varepsilon4 allele (25.9 pg/ml vs. 21.2 pg/ml, P=0.01), while mean plasma levels of Abeta1-40 did not vary by APOE genotype. These results support the hypothesis that Abeta1-42 plays an important role in the pathogenesis of dementia associated with DS, as it does in Alzheimer's disease, and that variations in plasma levels may be related to disease progression.

Adult↗
PubMed2001

Incidence of AD in African-Americans, Caribbean Hispanics, and Caucasians in northern Manhattan.

OBJECTIVE: To compare the incidence rates for AD among elderly African-American, Caribbean Hispanic, and white individuals and to determine whether coincident cerebrovascular disease contributes to the inconsistency in reported differences among ethnic groups. METHODS: This was a population-based, longitudinal study over a 7-year period in the Washington Heights and Inwood communities of New York City. Annual incidence rates for AD were calculated and compared by ethnic group, and cumulative incidence adjusted for differences in education, diabetes, cardiovascular risk factors, and stroke was calculated. RESULTS: The age-specific incidence rate for probable and possible AD was 1.3% (95% CI, 0.8 to 1.7) per person-year between the ages of 65 and 74 years, 4.0% (95% CI, 3.2 to 4.8) per person-year between ages 75 and 84 years, and 7.9% (95% CI, 5.5 to 10.5) per person-year for ages 85 and older. Compared to white individuals, the cumulative incidence of AD to age 90 years was increased twofold among African-American and Caribbean Hispanic individuals. Adjustment for differences in number of years of education, illiteracy, or a history of stroke, hypertension, heart disease, or diabetes did not change the disproportionate risks among the three ethnic groups. CONCLUSION: The incidence rate for AD was significantly higher among African-American and Caribbean Hispanic elderly individuals compared white individuals. The presence of clinically apparent cardiovascular or cerebrovascular disease did not contribute to the increased risk of disease. Because the proportion of African-American and Caribbean Hispanic individuals reaching ages 65 and older in the United States is increasing more rapidly than the proportion of white individuals, it is imperative that this disparity in health among the elderly be understood.

Aged↗
PubMed2001

Autoantibodies to amyloid-beta and Alzheimer's disease.

Immunization against amyloid-beta has been suggested as a possible preventive or therapeutic treatment for Alzheimer's disease. We hypothesized that some individuals may have autoantibodies to amyloid-beta and that this may be protective. We analyzed the plasma of 365 individuals, drawn from a larger longitudinal epidemiological study, for the presence of antibodies to amyloid-beta. There were detectable but very low levels of anti-amyloid-beta antibodies in just over 50% of all samples and modest levels in under 5% of all samples. However, neither the presence nor the level of anti-amyloid-beta antibodies correlated with the likelihood of developing dementia or with plasma levels of amyloid-beta peptide. These data suggest that low levels of anti-amyloid-beta autoantibodies are frequent in the elderly population but do not confer protection against developing dementia.

Aged↗
PubMed2001

Natural history of Alzheimer's disease.

Alzheimer's disease (AD) is the principal cause of dementia in the elderly, and affects about 15 million people worldwide. The earliest symptom is usually an insidious impairment of memory. As the disease progresses, there is increasing impairment of language and other cognitive functions. Problems occur with naming and word-finding, and later with verbal and written comprehension and expression. Visuospatial, analytic and abstract reasoning abilities, judgment, and insight become affected. Behavioral changes may include delusions, hallucinations, irritability, agitation, verbal or physical aggression, wandering, and disinhibition. Ultimately, there is loss of self-hygiene, eating, dressing, and ambulatory abilities, and incontinence and motor dysfunction. Before diagnosis of AD, individuals may have memory complaints, which represent a period of mild cognitive impairment (MCI). Before MCI, there is a prodromal, ill-defined presymptomatic period of disease ('pre-MCI"). In this review, we particularly focus on these earliest stages. We also discuss the more advanced stages of AD, and address factors that may influence disease course. Understanding the natural history of AD will allow better targeting of the disease-modifying treatments that are on the horizon.

Age Factors↗
PubMed2001

Circuit mechanisms underlying memory encoding and retrieval in the long axis of the hippocampal formation.

Circuits within the hippocampal formation are active during memory processing. Here we used functional magnetic resonance imaging (fMRI) to examine multiple sites across the long axis of the hippocampal formation while subjects performed different phases of an associative memory task, learning to associate faces with names. Viewing faces and hearing names in isolation resulted in separate hippocampal activation patterns. Pairing faces with names resulted a spatially redistributed activation pattern, rather than a simple summation of the activation patterns resulting from viewing faces and hearing names in isolation. Recalling names when cued with faces reactivated a pattern similar to that found during paired training. Finally, the activation patterns representing faces and names were found to be experience dependent, emerging with repeated exposure. Interpreted in the context of hippocampal anatomy and physiology, these findings reveal hippocampal circuit mechanisms that underlie memory encoding and retrieval.

Adult↗
PubMed2001

Persistent mobility deficit in the absence of deficits in activities of daily living: a risk factor for mortality.

OBJECTIVES: To investigate the extent to which self-reported mobility deficit in the absence of impairment in activities of daily living (ADL) is associated with elevated mortality risk. DESIGN: Prospective cohort study, with annual assessments of mobility and ADL status and ongoing monitoring of vital status. SETTING: Population-based cohort drawn from Medicare enrollees in New York City. PARTICIPANTS: One thousand two hundred ninety-eight older adults reporting functional status at baseline (1992-1994) and 2 years later. MEASUREMENTS: Subjects reported mobility (e.g., walking, climbing stairs, and rising from a chair) and ADL (e.g., bathing, toilet use, dressing, grooming, and feeding) limitations. Two-year functional status trajectories were noted. We used two additional follow-up periods, at 2 and 4 years, to examine the likelihood that older people with mobility deficit may face an increased risk of death without first passing through a state of enduring ADL disability. RESULTS: At 2 years, 12.7% had incident mobility deficit without ADL disability, and 21.3% were persistently disabled in mobility without ADL disability. Relative to subjects free of disability at baseline and follow-up, risk of mortality in the incident mobility deficit group was elevated at 2 and 4 years but did not achieve statistical significance. By contrast, for subjects with persistent mobility impairment who did not report ADL impairment, the mortality risk was significantly elevated both at 2 years (relative risk (RR) = 2.5; 95% confidence interval (CI) = 1.1-5.7)) and 4 years (RR = 2.9; 95% CI = 1.7-4.9)) of follow-up. Mortality was significantly elevated in this group in analyses restricted to respondents with no or only one comorbid condition. CONCLUSION: Continuing, self-reported mobility impairment in the absence of ADL deficit is a risk factor for mortality. Older people with self-reported mobility deficit face an increased risk of mortality without first passing through enduring states of ADL disability.

Activities of Daily Living↗
PubMed2000

Alzheimer's disease in the parents of women with trisomic spontaneous abortions.

We tested whether familial aggregation of Down syndrome and Alzheimer's disease (AD) is present for trisomies of other autosomes. We compared rates of Alzheimer-like dementia in the parents of women with trisomic pregnancy losses (n = 109) with those in parents of women with chromosomally normal losses (n = 151) and births (n = 216). Relative risks of Alzheimer-like dementia in parents of women with trisomic losses were 1.2 (95% CI 0.6, 2.2) and 0.9 (95% CI 0.5, 1.5) in comparison to parents of women with chromosomally normal losses and births, respectively. Associations were similar among women whose index pregnancy occurred before age 35 or later. Our data do not support an association between the occurrence of AD and trisomy of all autosomal chromosomes. They raise the possibility that familial aggregation with AD is specific to trisomy 21.

Abortion, Spontaneous↗
PubMed2000

Endogenous estrogen levels and Alzheimer's disease among postmenopausal women.

BACKGROUND: Although several studies have suggested that hormone replacement therapy lowers the risk of AD among postmenopausal women, few studies have evaluated the relationship of endogenous estrogen levels and AD. The current study investigated whether serum estrone and estradiol levels were related to the presence of AD among postmenopausal women not currently taking hormone replacement therapy. METHODS: Using a case-control design, we examined an ethnically diverse sample of postmenopausal women who met National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD (n = 50) and nondemented controls (n = 93). All women were participants in a study of aging and dementia and were seen consecutively between August 1997 and October 1998. RESULTS: Patients with AD had lower estradiol (F[1,141] = 8.3, p = 0.005) levels than did normal controls. Patients also had lower estrone levels; however, this comparison did not quite meet significance criteria (F[1,141] = 3.6, p = 0.06). Compared to estradiol levels >20 pg/mL, women with AD were four to six times more likely to have levels <20 pg/mL after adjusting for age, years of education, presence of an APOE-epsilon4 allele, ethnicity, and body mass index. There were no significant differences in frequency of AD among women within different quartiles of estrone after adjusting for potential confounds. CONCLUSIONS: The results of this preliminary case-control study suggest that estradiol levels may decline significantly in women in whom AD develops.

Aged↗
PubMed2000

Mitochondrial DNA mutations in complex I and tRNA genes in Parkinson's disease.

OBJECTIVE: To identify mitochondrial DNA (mtDNA) mutations that predispose to PD. BACKGROUND: Mitochondrial complex I activity is deficient in PD. mtDNA mutations may account for the defect, but the specific mutations have not been identified. METHODS: Complete sequencing was performed of all mtDNA-encoded complex I and transfer RNA (tRNA) genes in 28 PD patients and 8 control subjects, as well as screening of up to 243 additional PD patients and up to 209 control subjects by restriction digests for selected mutations. RESULTS: In the PD patients, 15 complex I missense mutations and 9 tRNA mutations were identified. After screening additional subjects, rare PD patients were found to carry complex I mutations that altered highly conserved amino acids. However, no significant differences were found in the frequencies of any mutations in PD versus control groups. The authors were unable to confirm previously reported associations of mutations at nucleotide positions (np) 4336, 5460, and 15927/8 with PD. Complex I mutations previously linked to Leber's hereditary optic neuropathy, one of which has been linked to atypical parkinsonism, were not associated with PD. CONCLUSIONS: mtDNA mutations with a high mutational burden (present in a high percentage of mtDNA molecules in an individual) in complex I or tRNA genes do not play a major role in the risk of PD in most PD patients. Further investigations are necessary to determine if any of the rare mtDNA mutations identified in PD patients play a role in the pathogenesis of PD in those few cases.

DNA, Mitochondrial↗
PubMed2000

The deletion polymorphism and Val1000Ile in alpha-2-macroglobulin and Alzheimer disease in Caribbean Hispanics.

The association between polymorphisms in the alpha-2-macroglobulin (a2m) gene and Alzheimer's disease remains in doubt because of conflicting results in independent case-control and family studies. We examined the association between Alzheimer's disease and alpha2m polymorphisms in Caribbean Hispanic families. The odds of having the alpha2m deletion/insertion polymorphism was increased 3-fold for family members with Alzheimer's disease compared to healthy family members, rising to 5-fold after adjusting for APOE-epsilon4. In contrast, there was no relationship between the alpha2m Val1000Ile polymorphism and Alzheimer's disease in these families. The inconsistencies in studies cited above and the modest association between alpha2m and Alzheimer's disease found in the Caribbean Hispanic families reported here, suggest that the overall effect of this gene on susceptibility is small and may be limited to certain populations or families.

Adult↗
PubMed2000

Familial aggregation of Alzheimer disease among whites, African Americans, and Caribbean Hispanics in northern Manhattan.

BACKGROUND: Alzheimer disease (AD) aggregates in families. OBJECTIVE: To compare the familial aggregation and lifetime risk of AD to the age of 90 years in the first-degree relatives of patients with AD and unrelated controls among Caribbean Hispanics, African Americans, and whites in Washington Heights, Manhattan, New York, NY. METHODS: Family history of AD and demographic information were obtained from informants of 435 patients with probable or possible AD concerning 1577 siblings and parents and from 1094 controls without dementia concerning 3952 siblings and parents. RESULTS: Lifetime risk of AD to the age of 90 years was 25.9% in relatives of patients and 19.1% in relatives of controls. Rate ratio (RR) for AD in relatives of patients compared with relatives of controls was 1.5 overall (95% confidence interval [CI], 1.2-1.9), and was greater for siblings (RR, 1.8; 95% CI, 1.2-2.5) than for parents (RR, 1.2; 95% CI, 0.9-1.8). Within ethnic groups, RR for AD among relatives was significantly elevated in whites (RR, 2.0; 95% CI, 1.2-3.3) and Hispanics (RR, 1.5; 95% CI, 1.1-2.1), but the difference did not reach statistical significance in African Americans (RR, 1.4; 95% CI, 0.7-2.7). Risk of AD was greater among relatives who were women compared with men (RR, 1.5; 95% CI, 1.2-1.9). CONCLUSIONS: Familial aggregation of AD was increased among families of patients compared with those of controls in all 3 ethnic groups. Risk of AD was highest among siblings and women relatives.

Aged↗
PubMed2000

Novel presenilin 1 mutations associated with early onset of dementia in a family with both early-onset and late-onset Alzheimer disease.

Two children of an adult with early-onset, autopsy-confirmed Alzheimer disease (AD) developed dementia in their late 20s and were subsequently found to have novel mutations in codon 434 of the presenilin 1 (PS1) gene on chromosome 14, a G-to-T substitution at nucleotide 1548 and a C-to-G substitution at nucleotide 1549. The younger of the 2 children had AD confirmed at postmortem examination. The disease course in these 3 individuals was characterized by cognitive and behavioral problems accompanied by myoclonus, seizures, and aphasia within 5 years after onset. Two grandparents had clinically diagnosed AD with stroke beginning at ages 78 and 66 years, but neither had a PS1 mutation. No other living family member was demented, nor did any other family member have the PS1 mutation. We conclude that the affected parent of the proband was a likely recent founder for these novel mutations in PS1. The family demonstrates the clinical and genetic heterogeneity of AD. Arch Neurol. 2000;57:1454-1457

Adult↗
PubMed2000

No association between a presenilin 1 polymorphism and Alzheimer disease.

BACKGROUND: Homozygosity of allele 1 of a presenilin 1 intron 8 polymorphism (PS1-1) has been associated with doubling of the risk of sporadic late-onset Alzheimer disease (LOAD), in some, but not all studies. OBJECTIVE: To genotype the PS1 intron 8 polymorphism in predominantly Hispanic families with LOAD to test for association and for linkage between this polymorphism and LOAD. DESIGN: A family-based, case-control, genetic-linkage study. SETTING: Predominantly Hispanic families were selected from probands who were part of a random sample of 2128 Medicare beneficiaries aged 65 years or older who were residing in the community of Washington Heights, which is located in the northern part of Manhattan, NY. PARTICIPANTS: Fifty-one families with 103 affected family members, 67 unaffected family members, and 7 family members with other diagnoses were genotyped for the PS1 polymorphism. All patients met National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for either probable or possible Alzheimer disease. Age was truncated at 55 years or older. MAIN OUTCOME MEASURES: Association analyses, conditional logistic regression, and traditional linkage methods were applied to the families for the PS1 polymorphism and for the presence of the gene for apolipoprotein E (APOE). Results of the association and conditional logistic regression analyses of PS1 intron 8 polymorphism were subsequently adjusted for the effect of APOE-epsilon4, sex, age, and education of each sibling. RESULTS: No association between the PS1 intron 8 polymorphism and LOAD was observed (relative risk, 0.99; 95% confidence interval, 0.3-3.4). An association between presence of the APOE-epsilon4 allele and LOAD (relative risk 4.05; 95% confidence interval, 1.3-12.5) was observed. CONCLUSION: We could not confirm the relationship between the PS1 intron 8 polymorphism and LOAD in this collection of families.

Aged↗