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Editorial: What Is Reasonable and Necessary for Alzheimer Patients from Randomized Clinical Trials to Clinical Practice? J Prev Alzheimers Dis 2023; 10:331-332. [PMID: 37357264 DOI: 10.14283/jpad.2023.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
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Editorial: Dietary Cholesterol and Dementia Risk. J Prev Alzheimers Dis 2023; 10:746-747. [PMID: 37874095 DOI: 10.14283/jpad.2023.66] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
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Editorial: Dementia Prevention: A Global Challenge in Urgent Need of Solutions. J Prev Alzheimers Dis 2022; 9:1-2. [PMID: 35098967 DOI: 10.14283/jpad.2022.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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At a Glance: An Update on Neuroimaging and Retinal Imaging in Alzheimer's Disease and Related Research. J Prev Alzheimers Dis 2022; 9:67-76. [PMID: 35098975 DOI: 10.14283/jpad.2022.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Neuroimaging serves a variety of purposes in Alzheimer's disease (AD) and related dementias (ADRD) research - from measuring microscale neural activity at the subcellular level, to broad topological patterns seen across macroscale-brain networks, and everything in between. In vivo imaging provides insight into the brain's structure, function, and molecular architecture across numerous scales of resolution; allowing examination of the morphological, functional, and pathological changes that occurs in patients across different AD stages (1). AD is a complex and potentially heterogenous disease, with no proven cure and no single risk factor to isolate and measure, whilst known risk factors do not fully account for the risk of developing this disease (2). Since the 1990's, technological advancements in neuroimaging have allowed us to visualise the wide organisational structure of the brain (3) and later developments led to capturing information of brain 'functionality', as well as the visualisation and measurement of the aggregation and accumulation of AD-related pathology. Thus, in vivo brain imaging has and will continue to be an instrumental tool in clinical research, mainly in the pre-clinical disease stages, aimed at elucidating the biological complex processes and interactions underpinning the onset and progression of cognitive decline and dementia. The growing societal burden of AD/ADRD means that there has never been a greater need, nor a better time, to use such powerful and sensitive tools to aid our understanding of this undoubtedly complex disease. It is by consolidating and reflecting on these imaging advancements and developing long-term strategies across different disciplines, that we can move closer to our goal of dementia prevention. This short commentary will outline recent developments in neuroimaging in the field of AD and dementia by first describing the historical context of AD classification and the introduction of AD imaging biomarkers, followed by some examples of significant recent developments in neuroimaging methods and technologies.
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Associations of Cardiovascular and Non-Cardiovascular Comorbidities with Dementia Risk in Patients with Diabetes: Results from a Large UK Cohort Study. J Prev Alzheimers Dis 2022; 9:86-91. [PMID: 35098977 DOI: 10.14283/jpad.2022.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
BACKGROUND Type 2 diabetes (T2D) is an established risk factor for dementia. However, it remains unclear whether the presence of comorbidities could further increase dementia risk in diabetes patients. OBJECTIVES To examine the associations between cardiovascular and non-cardiovascular comorbidities and dementia risk in T2D patients. DESIGN Population-based cohort study. SETTING The UK Clinical Practice Research Datalink (CPRD). PARTICIPANTS 489,205 T2D patients aged over 50 years in the UK CPRD. MEASUREMENTS Major cardiovascular and non-cardiovascular comorbidities were extracted as time-varying exposure variables. The outcome event was dementia incidence based on dementia diagnosis or dementia-specific drug prescription. RESULTS During a median of six years follow-up, 33,773 (6.9%) incident dementia cases were observed. Time-varying Cox regressions showed T2D patients with stroke, peripheral vascular disease, atrial fibrillation, heart failure or hypertension were at higher risk of dementia compared to those without such comorbidities (HR [95% CI] = 1.64 [1.59-1.68], 1.37 [1.34-1.41], 1.26 [1.22-1.30], 1.15 [1.11-1.20] or 1.10 [1.03-1.18], respectively). Presence of chronic obstructive pulmonary disease or chronic kidney disease was also associated with increased dementia risk (HR [95% CI] = 1.05 [1.01-1.10] or 1.11 [1.07-1.14]). CONCLUSIONS A range of cardiovascular and non-cardiovascular comorbidities were associated with further increases of dementia risk in T2D patients. Prevention and effective management of these comorbidities may play a significant role in maintaining cognitive health in T2D patients.
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Vitamin B12 and Folate Status in Cognitively Healthy Older Adults and Associations with Cognitive Performance. J Nutr Health Aging 2021; 25:287-294. [PMID: 33575718 DOI: 10.1007/s12603-020-1489-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVES To determine prevalence of vitamin B12 and folate deficiency and associations with cognitive performance in participants recruited for the Cognitive Health in Ageing Register: Investigational, Observational, and Trial Studies in Dementia Research: Prospective Readiness cOhort Study (CHARIOTPRO) SubStudy (CPRO-SS). DESIGN Cross-sectional analysis of data collected in the screening phase for the CPRO-SS. SETTING Participants were recruited from the Chariot Register at Imperial College London comprising approximately 39,000 community dwelling volunteers. PARTICIPANTS Community dwelling individuals aged 60-85 years with B vitamin biomarker measures available were included (n=1946). After medical history and other exclusions, 1347 cognitively healthy participants were included for analysis of cognitive data. MEASUREMENTS Cognitive status was assessed with the Repeatable Battery for Neuropsychological Status (RBANS). Assays included vitamin B12 and folate, followed by serum methylmalonic acid and homocysteine levels for those with low vitamin B12. Gender-specific linear regression analysis was performed for associations between cognition and biomarkers. Non-gender specific regression for groups graded by B vitamin deficiency severity were also performed. RESULTS Vitamin B12 deficiency (<148pmol/L) was found in 17.2% of individuals and folate deficiency (<10nmol/L) in 1% of our participants. Low vitamin B12 was associated with poorer memory (p<0.03) in men. A high BMI predicted poorer attention and visuospatial indices (p<0.05). A regression analysis by B12 level revealed associations with poorer attention (β -6.46; p=0.004) for the deficient group and with immediate memory (β -2.99; p=0.019) for those categorised as severely deficient. CONCLUSION Older men and women are prone to vitamin B12 deficiency with associated subtle and different domain-specific disruptive effects in measures of memory and attention. Elevated homocysteine and methylmalonic acid contributed to poorer cognitive performance. Novel groups at particular risk of cognitive deficit were identified for future interventional studies in this field.
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Editorial: WHO Guidelines on Community-Level Interventions to Manage Declines in Intrinsic Capacity: The Road for Preventing Cognitive Declines in Older Age? JPAD-JOURNAL OF PREVENTION OF ALZHEIMERS DISEASE 2019; 5:165-167. [PMID: 29972207 DOI: 10.14283/jpad.2018.26] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Concept of decline in “Intrinsic Capacities” (IC) from W.H.O Current Aging program (1, 2) prompts us to reposition prevention of cognitive decline and memory disorders with advancing age. In the new conceptual framework, Healthy Ageing is not defined as life free of diseases (disease can occur at any age) but, rather, as «the process of developing and maintaining the functional ability that enables wellbeing in older age» (1). This is a significant departure from the key strategy of current health care systems that are mainly designed to identify and treat acute episodes of (and chronic) illnesses, rather than maintaining individuals’ Intrinsic Capacities IC across the life course (1). Hence, there is an urgent need to change the strategic emphasis of health care systems from focusing on acute conditions to promoting integrated care aimed at maintaining functional abilities and well-being as an effective approach to promote healthy ageing.
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Cortical Lewy bodies and Aβ burden are associated with prevalence and timing of dementia in Lewy body diseases. Neuropathol Appl Neurobiol 2015; 42:436-50. [DOI: 10.1111/nan.12294] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/24/2015] [Accepted: 11/03/2015] [Indexed: 01/16/2023]
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Genome-wide association study of recurrent major depressive disorder in two European case-control cohorts. Mol Psychiatry 2010; 15:589-601. [PMID: 19107115 DOI: 10.1038/mp.2008.131] [Citation(s) in RCA: 192] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Major depressive disorder (MDD) is a highly prevalent disorder with substantial heritability. Heritability has been shown to be substantial and higher in the variant of MDD characterized by recurrent episodes of depression. Genetic studies have thus far failed to identify clear and consistent evidence of genetic risk factors for MDD. We conducted a genome-wide association study (GWAS) in two independent datasets. The first GWAS was performed on 1022 recurrent MDD patients and 1000 controls genotyped on the Illumina 550 platform. The second was conducted on 492 recurrent MDD patients and 1052 controls selected from a population-based collection, genotyped on the Affymetrix 5.0 platform. Neither GWAS identified any SNP that achieved GWAS significance. We obtained imputed genotypes at the Illumina loci for the individuals genotyped on the Affymetrix platform, and performed a meta-analysis of the two GWASs for this common set of approximately half a million SNPs. The meta-analysis did not yield genome-wide significant results either. The results from our study suggest that SNPs with substantial odds ratio are unlikely to exist for MDD, at least in our datasets and among the relatively common SNPs genotyped or tagged by the half-million-loci arrays. Meta-analysis of larger datasets is warranted to identify SNPs with smaller effects or with rarer allele frequencies that contribute to the risk of MDD.
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Risk prediction of prevalent diabetes in a Swiss population using a weighted genetic score--the CoLaus Study. Diabetologia 2009; 52:600-8. [PMID: 19139842 DOI: 10.1007/s00125-008-1254-y] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/03/2008] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Several susceptibility genes for type 2 diabetes have been discovered recently. Individually, these genes increase the disease risk only minimally. The goals of the present study were to determine, at the population level, the risk of diabetes in individuals who carry risk alleles within several susceptibility genes for the disease and the added value of this genetic information over the clinical predictors. METHODS We constructed an additive genetic score using the most replicated single-nucleotide polymorphisms (SNPs) within 15 type 2 diabetes-susceptibility genes, weighting each SNP with its reported effect. We tested this score in the extensively phenotyped population-based cross-sectional CoLaus Study in Lausanne, Switzerland (n = 5,360), involving 356 diabetic individuals. RESULTS The clinical predictors of prevalent diabetes were age, BMI, family history of diabetes, WHR, and triacylglycerol/HDL-cholesterol ratio. After adjustment for these variables, the risk of diabetes was 2.7 (95% CI 1.8-4.0, p = 0.000006) for individuals with a genetic score within the top quintile, compared with the bottom quintile. Adding the genetic score to the clinical covariates improved the area under the receiver operating characteristic curve slightly (from 0.86 to 0.87), yet significantly (p = 0.002). BMI was similar in these two extreme quintiles. CONCLUSIONS/INTERPRETATION In this population, a simple weighted 15 SNP-based genetic score provides additional information over clinical predictors of prevalent diabetes. At this stage, however, the clinical benefit of this genetic information is limited.
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Abstract
BACKGROUND PINK1 loss-of-function causes recessive, early-onset parkinsonism. In Tunisia there is a high rate of consanguineous marriage but PINK1 carrier frequency and disease prevalence have yet to be assessed. OBJECTIVES The frequency of PINK1 mutations in familial parkinsonism, community-based patients with idiopathic Parkinson disease (PD) (non-familial PD), and control subjects was determined. Demographic and clinical characteristics of individuals with PINK1 homozygous or heterozygous variants, or without PINK1 mutations, were compared. METHODS A total of 92 kindreds (with 208 affected and 340 unaffected subjects), 240 nonfamilial PD, and 368 control participants were recruited from the Institut National de Neurologie, Tunis. Clinical examinations included Hoehn &Yahr, UPDRS, and Epworth scales. PINK1 sequencing and dosage analysis was performed in familial index patients, the variants identified screened in all subjects. Parkin and LRRK2 genes were also examined. RESULTS Four PINK1 homozygous mutations, three novel (Q129X, Q129fsX157, G440E, and one previously reported; Q456X), segregate with parkinsonism in 46 individuals in 14 of 92 families (15%). Six of 240 patients with nonfamilial PD were found with either homozygous Q456X or Q129X (2.5%) substitutions. In patients with familial disease, PINK1 homozygotes were younger at disease onset (36 +/- 12 years) than noncarriers (57 +/- 15 years) and more often had an akinetic-rigid presentation at examination and slow progression. CONCLUSIONS Segregation of PINK1 mutations with parkinsonism within families, and frequency estimates within population controls, suggested only four PINK1 mutations were pathogenic. Several PINK1 sequence variants are potentially benign and there was no evidence that PINK1 heterozygosity increases susceptibility to idiopathic Parkinson disease.
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Abstract
BACKGROUND Genetic epidemiology data suggest that younger age of onset is associated with family history (FH) of depression. The present study tested whether the presence of FH for depression or anxiety in first-degree relatives determines younger age of onset for depression. METHOD A sample of 1022 cases with recurrent major depressive disorder (MDD) was recruited at the Max Planck Institute and at two affiliated hospitals. Patients were assessed using the Schedules for Clinical Assessment in Neuropsychiatry and questionnaires including demographics, medical history, questions on the use of alcohol and tobacco, personality traits and life events. Survival analysis and the Cox proportional hazard model were used to determine whether FH of depression signals earlier age of onset of depression. RESULTS Patients who reported positive FH had a significantly earlier age of onset than patients who did not report FH of depression (log-rank=48, df=1, p<0.0001). The magnitude of association of FH varies by age of onset, with the largest estimate for MDD onset before age 20 years (hazard ratio=2.2, p=0.0009), whereas FH is not associated with MDD for onset after age 50 years (hazard ratio=0.89, p=0.5). The presence of feelings of guilt, anxiety symptoms and functional impairment due to depressive symptoms appear to characterize individuals with positive FH of depression. CONCLUSIONS FH of depression contributes to the onset of depression at a younger age and may affect the clinical features of the illness.
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Abstract
Advances in technologies and the availability of a single nucleotide polymorphism (SNP) map are beginning to show the true potential for the human genome project to affect patient healthcare. A whole genome scan, the use of 100000-300000 SNPs across the genome, is now possible. Use of traditional approaches and the whole genome scan will result in identification of disease susceptibility genes and development of many new treatments in the longer term. In the shorter term, the goal will be to predict those patients at risk to experience an adverse reaction or those with a high probability for improved efficacy (i.e. pharmacogenetics). As progress is made in the area of disease genetics and pharmacogenetics, our understanding of disease susceptibility and its interrelationship with drug response will improve, making targeted therapy (i.e. the right drug to the right patient) a reality.
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Abstract
Recently, the authors demonstrated linkage in idiopathic PD to a region on chromosome 8p that contains the N-acetyltransferase genes, NAT1 and NAT2. The authors examined NAT1 and NAT2 for association with PD using family-based association methods and single nucleotide polymorphisms (SNPs). The authors did not find evidence for association with increased risk for PD between any individual NAT1 or NAT2 SNP or acetylation haplotype (N = 397 families, 1,580 individuals).
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Hereditary motor neuronopathies. Rev Neurol (Paris) 2002; 158:1220-4. [PMID: 12690745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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Abstract
CONTEXT The relative contribution of genes vs environment in idiopathic Parkinson disease (PD) is controversial. Although genetic studies have identified 2 genes in which mutations cause rare single-gene variants of PD and observational studies have suggested a genetic component, twin studies have suggested that little genetic contribution exists in the common forms of PD. OBJECTIVE To identify genetic risk factors for idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS Genetic linkage study conducted 1995-2000 in which a complete genomic screen (n = 344 markers) was performed in 174 families with multiple individuals diagnosed as having idiopathic PD, identified through probands in 13 clinic populations in the continental United States and Australia. A total of 870 family members were studied: 378 diagnosed as having PD, 379 unaffected by PD, and 113 with unclear status. MAIN OUTCOME MEASURES Logarithm of odds (lod) scores generated from parametric and nonparametric genetic linkage analysis. RESULTS Two-point parametric maximum parametric lod score (MLOD) and multipoint nonparametric lod score (LOD) linkage analysis detected significant evidence for linkage to 5 distinct chromosomal regions: chromosome 6 in the parkin gene (MLOD = 5.07; LOD = 5.47) in families with at least 1 individual with PD onset at younger than 40 years, chromosomes 17q (MLOD = 2.28; LOD = 2.62), 8p (MLOD = 2.01; LOD = 2.22), and 5q (MLOD = 2.39; LOD = 1.50) overall and in families with late-onset PD, and chromosome 9q (MLOD = 1.52; LOD = 2.59) in families with both levodopa-responsive and levodopa-nonresponsive patients. CONCLUSIONS Our data suggest that the parkin gene is important in early-onset PD and that multiple genetic factors may be important in the development of idiopathic late-onset PD.
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MESH Headings
- Adult
- Age of Onset
- Aged
- Antiparkinson Agents/therapeutic use
- Chromosomes, Human, Pair 17
- Chromosomes, Human, Pair 3
- Chromosomes, Human, Pair 5
- Chromosomes, Human, Pair 6
- Chromosomes, Human, Pair 8
- Chromosomes, Human, Pair 9
- Drug Resistance
- Genetic Predisposition to Disease
- Genotype
- Humans
- Levodopa/therapeutic use
- Ligases/genetics
- Lod Score
- Microsatellite Repeats
- Middle Aged
- Parkinson Disease/drug therapy
- Parkinson Disease/epidemiology
- Parkinson Disease/genetics
- Risk Factors
- Ubiquitin-Protein Ligases
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Abstract
CONTEXT The human tau gene, which promotes assembly of neuronal microtubules, has been associated with several rare neurologic diseases that clinically include parkinsonian features. We recently observed linkage in idiopathic Parkinson disease (PD) to a region on chromosome 17q21 that contains the tau gene. These factors make tau a good candidate for investigation as a susceptibility gene for idiopathic PD, the most common form of the disease. OBJECTIVE To investigate whether the tau gene is involved in idiopathic PD. DESIGN, SETTING, AND PARTICIPANTS Among a sample of 1056 individuals from 235 families selected from 13 clinical centers in the United States and Australia and from a family ascertainment core center, we tested 5 single-nucleotide polymorphisms (SNPs) within the tau gene for association with PD, using family-based tests of association. Both affected (n = 426) and unaffected (n = 579) family members were included; 51 individuals had unclear PD status. Analyses were conducted to test individual SNPs and SNP haplotypes within the tau gene. MAIN OUTCOME MEASURE Family-based tests of association, calculated using asymptotic distributions. RESULTS Analysis of association between the SNPs and PD yielded significant evidence of association for 3 of the 5 SNPs tested: SNP 3, P =.03; SNP 9i, P =.04; and SNP 11, P =.04. The 2 other SNPs did not show evidence of significant association (SNP 9ii, P =.11, and SNP 9iii, P =.87). Strong evidence of association was found with haplotype analysis, with a positive association with one haplotype (P =.009) and a negative association with another haplotype (P =.007). Substantial linkage disequilibrium (P<.001) was detected between 4 of the 5 SNPs (SNPs 3, 9i, 9ii, and 11). CONCLUSIONS This integrated approach of genetic linkage and positional association analyses implicates tau as a susceptibility gene for idiopathic PD.
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Mapping of the second Friedreich's ataxia (FRDA2) locus to chromosome 9p23-p11: evidence for further locus heterogeneity. Neurogenetics 2001; 3:127-32. [PMID: 11523563 DOI: 10.1007/s100480100112] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Friedreich's ataxia (FRDA), the most-common form of autosomal recessive ataxia, is inherited in most cases by a large expansion of a GAA triplet repeat in the first intron of the frataxin (X25) gene. Genetic heterogeneity in FRDA has been previously reported in typical FRDA families that do not link to the FRDA locus on chromosome 9q13. We report localization of a second FRDA locus (FRDA2) to chromosome 9p23-9p11, and we provide evidence for further genetic heterogeneity of the disease, in a family with the classic FRDA phenotype.
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Fundamental gating mechanism of nicotinic receptor channel revealed by mutation causing a congenital myasthenic syndrome. J Gen Physiol 2000; 116:449-62. [PMID: 10962020 PMCID: PMC2233692 DOI: 10.1085/jgp.116.3.449] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
We describe the genetic and kinetic defects in a congenital myasthenic syndrome due to the mutation epsilonA411P in the amphipathic helix of the acetylcholine receptor (AChR) epsilon subunit. Myasthenic patients from three unrelated families are either homozygous for epsilonA411P or are heterozygous and harbor a null mutation in the second epsilon allele, indicating that epsilonA411P is recessive. We expressed human AChRs containing wild-type or A411P epsilon subunits in 293HEK cells, recorded single channel currents at high bandwidth, and determined microscopic rate constants for individual channels using hidden Markov modeling. For individual wild-type and mutant channels, each rate constant distributes as a Gaussian function, but the spread in the distributions for channel opening and closing rate constants is greatly expanded by epsilonA411P. Prolines engineered into positions flanking residue 411 of the epsilon subunit greatly increase the range of activation kinetics similar to epsilonA411P, whereas prolines engineered into positions equivalent to epsilonA411 in beta and delta subunits are without effect. Thus, the amphipathic helix of the epsilon subunit stabilizes the channel, minimizing the number and range of kinetic modes accessible to individual AChRs. The findings suggest that analogous stabilizing structures are present in other ion channels, and possibly allosteric proteins in general, and that they evolved to maintain uniformity of activation episodes. The findings further suggest that the fundamental gating mechanism of the AChR channel can be explained by a corrugated energy landscape superimposed on a steeply sloped energy well.
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Distal hereditary motor neuronopathy of the Jerash type. Ann N Y Acad Sci 1999; 883:65-8. [PMID: 10586232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
A novel form of autosomal recessive distal hereditary motor neuronopathy (distal HMN) is reported. The presence of pyramidal signs within the early stages of the disease with persistence of knee hyperreflexia form distinctive clinical features. We have mapped the HMN-J gene to chromosome 9p21.1-p12, within an estimated interval of 1.2-Mb.
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Distal hereditary motor neuronopathy of the Jerash type. Ann N Y Acad Sci 1999; 883:439-42. [PMID: 10586267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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Introduction to this special issue. Intelligent data analysis in electromyography and electroneurography. Med Eng Phys 1999; 21:379-88. [PMID: 10624735 DOI: 10.1016/s1350-4533(99)00084-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The Charcot-Marie-Tooth (CMT) neuropathies are a group of disorders exhibiting neurophysical, pathological and genetic heterogeneity. CMT2 is a diagnostic subtype of this group of disorders characterized by variable expression and age-of-onset and normal or slightly diminished nerve conduction velocities. Previously, linkage and heterogeneity had been reported in CMT2 with linked families localizing to chromosome 1p (CMT2A). Recently a second CMT2 locus has been described on chromosome 7 in a single large CMT2 family (CMT2D). We have performed pedigree linkage analysis on 15 CMT2 families (N = 371 individuals, 106 affected family members) and have confirmed linkage to chromosome 7. Furthermore, using both admixture and multipoint linkage analysis we show conclusive evidence for additional heterogeneity within this clinical subtype with evidence of families that exclude linkage to both the CMT2D and CMT2A regions. In addition, unlike the previous report we found no obvious consistent clinical differences between the linked family types.
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Mapping of the familial infantile myasthenia (congenital myasthenic syndrome type Ia) gene to chromosome 17p with evidence of genetic homogeneity. Hum Mol Genet 1997; 6:635-40. [PMID: 9097970 DOI: 10.1093/hmg/6.4.635] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Familial infantile myasthenia is an autosomal recessive disorder, recently classified as congenital myasthenic syndrome type Ia. Onset of symptoms is at birth to early childhood with significant myasthenic weakness and possible respiratory distress, followed later in life by symptoms of mild to moderate myasthenia. Thirty-six patients of 12 families, seven of them consanguineous, were used to map the familial infantile myasthenia gene. A combination of linkage search through the genome, DNA pooling and homozygosity mapping were employed resulting in the localisation of this disease locus to the telomeric region of chromosome 17p. A maximum lod score of 9.28 at theta = 0.034 was obtained between the disease locus and marker locus D17S1537. Haplotype analysis showed all families to be consistent with linkage to this region thus providing evidence for genetic homogeneity of familial infantile myasthenia. Multipoint linkage analysis mapped the disease gene in the approximately 4.0 cM interval between marker loci D17S1537 and D17S1298 with a maximum multipoint lod score of 12.07. Haplotype analysis and homozygosity by descent in affected individuals of the consanguineous families revealed results in agreement with the confinement of the familial infantile myasthenia region within the interval between marker loci D17S1537 and D17S1298.
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Mapping of a distal form of spinal muscular atrophy with upper limb predominance to chromosome 7p. Hum Mol Genet 1995; 4:1629-32. [PMID: 8541851 DOI: 10.1093/hmg/4.9.1629] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
An autosomal dominant distal form of spinal muscular atrophy mainly affecting the upper limbs with a mean age of onset of 17 years has been identified in a large Bulgarian family. Linkage of the above family to the spinal muscular atrophy type I, II and III locus on chromosome 5 has been excluded. In an attempt to map this disease gene we have analysed individuals of this family, with more than 140 microsatellite polymorphic markers of the human genome. A maximum lod score of 5.99 at theta = 0.007 has been obtained with locus D7S795. We have thus mapped the gene for this hereditary form of distal spinal muscular atrophy to chromosome 7p.
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Efficient training of neural network models in classification of electromyographic data. Med Biol Eng Comput 1995; 33:499-503. [PMID: 7666701 DOI: 10.1007/bf02510537] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
Cyprus is an island in the eastern Mediterranean basin inhabited by people of Caucasian extraction, mostly Greek-Cypriots. The most common inherited disease among Caucasians is cystic fibrosis (CF). Although no careful scientific study had ever been done the impression was that CF was extremely rare among the Greek-Cypriots, with an incidence estimated at around 1:30,000. About 2 years ago, we introduced molecular diagnostic methodology in an effort to assist clinicians in safer diagnosis of patients presenting with atypical CF symptomatology, and also for testing the hypothesis that mutations that cause milder phenotypes might be responsible for misdiagnosis or for missing entirely some cases of CF. Initial screening for delta F508 revealed that it is indeed rare in the general population. Further screening of suspected CF patients revealed a novel mutation that converted leucine at position 346 to proline (L346P) in two unrelated families. The second CF mutation was delta F508 and 1677delTA in the two families respectively, both reportedly associated with severe phenotypes. Yet our patients did not present with typical CF pictures possibly because of the dominant nature of this novel mild mutation in exon 7. Symptoms included failure to thrive, chest infections and electrolyte disturbances. These findings raise the possibility that Cyprus might have been spared very severe CF phenotypes but not cystic fibrosis transmembrane conductance regulator (CFTR) mutations.
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Localization of a gene (CMT2A) for autosomal dominant Charcot-Marie-Tooth disease type 2 to chromosome 1p and evidence of genetic heterogeneity. Genomics 1993; 17:370-5. [PMID: 8406488 DOI: 10.1006/geno.1993.1334] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Charcot-Marie-Tooth (CMT) disease type 2 (CMT2) is an inherited peripheral neuropathy characterized by variable age of onset and normal or slightly diminished nerve conduction velocity. CMT2 is pathologically and genetically distinct from CMT type 1 (CMT1). While CMT1 has been shown to be genetically heterogeneous, no chromosomal localization has been established for CMT2. We have performed pedigree linkage analysis in six large autosomal dominant CMT2 families and have demonstrated linkage and heterogeneity to a series of microsatellites (D1S160, D1S170, D1S244, D1S228 and D1S199) in the distal region of the short arm of chromosome 1. Significant evidence for heterogeneity was found using admixture analysis and the two-point lod scores. Admixture analyses using the multipoint results for the markers D1S244, D1S228, and D1S199 supported the two-point findings. Three families, DUK662, DUK1241, and 1523 gave posterior probabilities of 1.0, 0.98, and 0.88 of being of the linked type. Multipoint analysis examining the "linked" families showed that the most favored location for the CMT2A gene is within the interval flanked by D1S244 and D1S228 (odds approximately 70:1 of lying within versus outside that interval). These findings suggest that the CMT2 phenotype is secondary to at least two different genes and demonstrate further heterogeneity in the CMT phenotype.
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New hereditary malformation syndrome of unusual facial appearance, skeletal deformities, and musculoskeletal and sensory defects. AMERICAN JOURNAL OF MEDICAL GENETICS 1992; 44:757-61. [PMID: 1481843 DOI: 10.1002/ajmg.1320440609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report on a new syndrome characterized by specific and striking facial abnormalities, arthrogrypotic skeletal deformities, and neuromuscular and sensory defects in a large Greek Cypriot family. The hereditary transmission appears to be autosomal dominant with quite variable expressivity.
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Abstract
The prevalence of multiple sclerosis (MS) was studied in the Greek-speaking population in the southwestern district of Paphos and the eastern Famagusta area and in the Troodos mountains in Cyprus. Excluding refugees from the northern part of the island, the MS prevalence was 44.5 per 100,000. This is a similar prevalence to that found in Sicily and shows that, like Sicily, Greek-speaking Cypriots have a medium to high and not a low MS prevalence. There was no significant difference in MS prevalence between the warm Paphos and Famagusta areas and the much colder mountainous areas. In one village, Liopetri, there were five families with definite MS (CDMS), and one patient with clinically probable MS (CPMS). Excluding refugees, the prevalence for CDMS and CPMS in this village was 240 per 100,000. All six families are probably related.
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