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Objectives: The favorable response to treatment with IV immunoglobulins and the presence of IgM antibodies to the glycolipid GM1 are indications that inflammation underlies multifocal motor neuropathy (MMN) pathogenesis. We investigated the association of MMN with human leukocyte antigen (HLA) class I and II antigens. Methods: HLA class I and II antigens of 74 Dutch patients with MMN and 700 controls were determined in a case-control study. Associations of HLA types with MMN disease characteristics were investigated. Results: Compared with controls, patients with MMN had higher frequencies of HLA-DRB1*15 (41 vs 24%, p = 0.0017). Disease characteristics were not associated with specific HLA types. Conclusions: Similar associations were found in patients with multiple sclerosis and women with chronic immune-mediated demyelinating neuropathy, which may suggest that these demyelinating disorders share pathogenic mechanisms.

Occupational and environmental exposures may contribute to the risk of developing sporadic amyotrophic lateral sclerosis (ALS). To summarize the available evidence, a systematic review of the literature on occupation as a potential determinant of ALS was performed according to the MOOSE guidelines. From MEDLINE, EMBASE, CINAHL, and Cochrane databases, selected studies were methodologically appraised according to Armon's classification system for ALS risk factor studies. Each occupation studied was reclassified according to the International Standard Classification of Occupations (ISCO-88). The vote-counting method was applied to summarize the data. Of 3773 potentially relevant studies, 51 were initially included. Of these, 12 studies provided risk estimates for individual occupations--one case-control, two register-based case-control, and nine register-based cohort studies. All studies fell into Armon's level of evidence class IV, indicating methodological limitations. Due to the heterogeneity of study methodology, data could not be pooled. The vote-counting method revealed several candidate occupations: veterinarians and other health workers, athletes, hairdressers, power-production plant, electrical and military workers. However, well designed studies with standardized assessment of occupation are needed to provide a more definitive answer about exogenous risk factors of ALS.

Monoclonal gammopathy in patients with amyotrophic lateral sclerosis (ALS) and related disorders has been reported in small studies but the validity of the reported associations remains uncertain. Presence of monoclonal gammopathy may indicate specific pathogenic pathways and may facilitate the development of novel treatment strategies. The objective of this large case-control study was to determine the prevalence of monoclonal gammopathy in motor neuron diseases (MND) and multifocal motor neuropathy (MMN). Monoclonal gammopathy was determined by immunoelectrophoresis and immunofixation in serum from 445 patients with ALS, 158 patients with progressive muscular atrophy (PMA), 60 patients with primary lateral sclerosis (PLS), 88 patients with MMN and in 430 matched healthy controls. Anti-ganglioside antibody titers were determined in sera from patients with MMN and PMA, and in ALS and PLS patients with monoclonal gammopathy. Logistic regression analysis was used to investigate associations of monoclonal gammopathy with motor neuron diseases and clinical characteristics. Neither ALS nor PLS was associated with monoclonal gammopathy. IgM monoclonal gammopathy was more frequent in patients with PMA (8 %) (OR = 4.2; p = 0.001) and MMN (7 %) (OR = 5.8; p = 0.002) than in controls (2 %). High titers of anti-GM1 IgM antibodies were present in 43 % of MMN patients and 7 % of PMA patients. Patients with PMA and IgM monoclonal gammopathy or anti-GM1 antibodies had a higher age at onset, more often weakness of upper legs and more severe outcome than patients with MMN. PMA and MMN, but not ALS and PLS, are significantly associated with IgM monoclonal gammopathy and anti-GM1 antibodies. These results may indicate that a subset of patients presenting with PMA share pathogenic mechanisms with MMN.

The pathogenesis of amyotrophic lateral sclerosis (ALS) is considered to be multifactorial. Several epidemiological studies showed a lower incidence of ALS in women than in men. This suggests a possible protective effect of female reproductive hormones. The aim of this study was to investigate the association between female reproductive hormones and ALS. We performed a population-based, case-control study in the Netherlands between 1st January 2006 and 1st December 2009. Only women with a natural menopause were included in the analysis. A total of 209 (85 %) of 246 female patients and 672 (93 %) of 719 controls returned a questionnaire on reproductive history to calculate the reproductive time-span and lifetime endogenous estrogen exposure (calculated by subtracting the duration of pregnancies and of oral contraceptive use, and the number of post-ovulatory weeks from the reproductive time-span). 131 (63 %) patients and 430 (64 %) age-matched, population-based controls had experienced a natural menopause. Multivariate analysis showed that increasing the reproductive time-span by a year decreases the risk of ALS with an OR of 0.95 (p = 0.005). Each year longer reproductive time-span [HR 0.90 (p = 0.01)] and lifetime endogenous estrogen exposure [HR 0.96 (p = 0.025)] were associated with a longer survival of ALS patients. The positive association of a longer reproductive time-span and susceptibility and survival of ALS might imply that longer exposure to female reproductive hormones has a neuroprotective effect on motor neurons.

Item does not contain fulltext Smoking has been posited as a possible risk factor for amyotrophic lateral sclerosis (ALS), but large population-based studies of patients with incident disease are still needed. The authors performed a population-based case-control study in the Netherlands between 2006 and 2009, including 494 patients with incident ALS and 1,599 controls. To prove the relevance of population-based incidence cohorts in case-control studies, the authors compared results with those from cohorts including patients with prevalent ALS and referral patients. Subjects were sent a questionnaire. Multivariate analyses showed an increased risk of ALS among current smokers (odds ratio = 1.38, 95% confidence interval (CI): 1.02, 1.88) in the incident patient group only. Cox regression models showed that current smoking was also independently associated with shorter survival (hazard ratio = 1.51, 95% CI: 1.07, 2.15), explaining the lack of association in the prevalent and referral patient groups. Current alcohol consumption was associated with a reduced risk of ALS (incident patient group: odds ratio = 0.52, 95% CI: 0.40, 0.75). These findings indicate that current smoking is associated with an increased risk of ALS, as well as a worse prognosis, and alcohol consumption is associated with a reduced risk of ALS, further corroborating the role of lifestyle factors in the pathogenesis of ALS. The importance of population-based incident patient cohorts in identifying risk factors is highlighted by this study.

International audience; ABSTRACT Objectives Reports of increased amyotrophic lateral sclerosis (ALS) with hyperlipidemia and elevated plasma homocysteine levels as well as cigarette-smoking and polymorphisms in angiogenic genes suggest a role for altered vascular homeostasis in ALS pathogenesis. We assessed the association between vascular risk factors and ALS. Methods Traditional cardiovascular risk factors (smoking, hypertension, hypercholesterolemia, diabetes and body mass index (BMI)) and cardiovascular disease prior to ALS onset established by a questionnaire were compared in 334 patients and 538 age- and sex-matched controls. Biochemical assessments (total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), hs-CRP, and homocysteine) at diagnosis were measured in blood samples of 303 patients with ALS and compared with prospectively collected data from 2100 population-based controls. Results Patients with ALS used cholesterol-lowering agents less frequently (OR=0.6, p=0.008), had a lower BMI (OR=0.9, p=0.001), a lower LDL/HDL ratio (women: OR=0.5, p

Background: Mutations in HFE, a gene defect that can disrupt iron metabolism, have been implicated in increasing the risk of developing amyotrophic lateral sclerosis (ALS). Objective: To further establish the association between ALS and HFE mutations by investigating whether HFE mutations are associated with an increased risk of developing ALS in a population in the Netherlands and by pooling our results with those from previous studies. Design: Retrospective study. Setting: Tertiary referral center for neuromuscular disorders. Participants: Genotyping for 2 common HFE mutations was performed in 289 patients with ALS and 5886 population-based controls in the Netherlands between January 1, 2000, and December 31, 2004. Main Outcome Measures: Development of ALS and clinical phenotype were compared among the different HFE genotypes, adjusting for known prognostic factors such as age at onset and sex. Results: Homozygosity for H63D was associated with an increased risk of developing ALS (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.1- 4.1). After pooling our results with those from previous studies, a positive association between H63D homozygotes (OR, 2.7; 95% CI, 1.7-4.4), heterozygotes (OR, 1.5; 95% CI, 1.0-2.1), and mutation carriers (OR, 1.7; 95% CI, 1.1-2.5) was found. Within the patient group, heterozygosity for the H63D mutation was associated with a higher age at onset. Conclusions: These findings suggest that H63D mutations in HFE play a role in the pathogenesis of ALS in various populations. This association might involve a later-onset subset of ALS.

Sequence alterations in the promoter region of the vascular endothelial growth factor (VEGF) gene have been implicated in increasing the risk of developing ALS. VEGF promoter haplotypes were determined in 373 patients with sporadic ALS and 615 matched healthy controls in The Netherlands. No significant association between the previously reported at-risk haplotypes and ALS was found. Pooling our results with the previously studied population still showed a significant association with the AAG haplotype.

Sporadic ALS is a multifactorial disease for which there are probably multiple genetic risk factors. An association with increased parental age might suggest there is a role for specific (epi) genetic changes. Previous studies have shown conflicting results on the association between parental age and the risk of ALS. A large, population based study might help in the search for specific (epi) genetic risk factors. We performed a population based, case-control study in the Netherlands. Date of birth of both mother and father was retrieved from the National Register. Multivariate logistic regression analysis was performed in 769 patients with sporadic ALS, 49 patients with a hexanucleotide repeat expansion in C9orf72, and 1929 age-, gender-and geographically-matched controls. Multivariate analyses showed no difference in either paternal or maternal age at delivery (adjusted for age of subject, age of other parent at delivery, and level of education) in patients with sporadic ALS, nor in patients with a hexanucleotide repeat expansion in C9orf72 compared to controls. In conclusion, parental age was not associated with an increased risk of ALS in our study. (Epi) genetic alterations that are associated with increased parental age are not, therefore, likely to contribute to the aetiology of sporadic ALS.