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Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects motor neurons. In Europe, disease-causing genetic variants have been identified in 40-70% of familial ALS patients and approximately 5% of sporadic ALS patients. In Norway, the contribution of genetic variants to ALS has not yet been studied. In light of the potential development of personalized medicine, knowledge of the genetic causes of ALS in a population is becoming increasingly important. The present study provides clinical and genetic data on familial and sporadic ALS patients in a Norwegian population-based cohort., Methods: Blood samples and clinical information from ALS patients were obtained at all 17 neurological departments throughout Norway during a 2-year period. Genetic analysis of the samples involved expansion analysis of C9orf72 and exome sequencing targeting 30 known ALS-linked genes. The variants were classified using genotype-phenotype correlations and bioinformatics tools., Results: A total of 279 ALS patients were included in the study. Of these, 11.5% had one or several family members affected by ALS, whereas 88.5% had no known family history of ALS. A genetic cause of ALS was identified in 31 individuals (11.1%), among which 18 (58.1%) were familial and 13 (41.9%) were sporadic. The most common genetic cause was the C9orf72 expansion (6.8%), which was identified in 8 familial and 11 sporadic ALS patients. Pathogenic or likely pathogenic variants of SOD1 and TBK1 were identified in 10 familial and 2 sporadic cases. C9orf72 expansions dominated in patients from the Northern and Central regions, whereas SOD1 variants dominated in patients from the South-Eastern region., Conclusion: In the present study, we identified several pathogenic gene variants in both familial and sporadic ALS patients. Restricting genetic analysis to only familial cases would miss more than 40 percent of those with a disease-causing genetic variant, indicating the need for genetic analysis in sporadic cases as well., (© 2022 The Author(s). Published by S. Karger AG, Basel.)

Background: Multiple sclerosis (MS) is a chronic disease of the central nervous system, often resulting in significant neurological disability. The causes of MS are not known; however, the incidence of MS is increasing, thereby suggesting that changes in lifestyle and/or environmental factors may be responsible. On this background, the Environmental Risk Factors in MS Study or EnvIMS study was designed to further explore the etiology of MS. The design and methodology are described, providing details to enable investigators to (i) use our experiences to design their own studies; (ii) take advantage of, and build on the methodological work completed for, the EnvIMS study; (iii) become aware of this data source that is available for use by the research community., Methods: EnvIMS is a multinational case-control study, enrolling 2,800 cases with MS and 5,012 population-based controls in Canada, Italy, Norway, Serbia and Sweden. The study was designed to investigate the most commonly implicated risk factors for MS etiology using a self-report questionnaire., Results/conclusions: The use of a common methodology to study MS etiology across several countries enhances the comparability of results in different geographic regions and research settings, reduces the resources required for study design and enhances the opportunity for data harmonization., (© 2015 S. Karger AG, Basel.)

Multiple sclerosis (MS) is a chronic disease of the central nervous system, pathologically characterized by inflammation, demyelination, and axonal damage, presumably auto-immune in nature. Complex interactions between genetic susceptibility and environmental factors, such as vitamin D status and primary Epstein-Barr virus infection in adolescence or later in life, probably determine the MS risk. Norway at a latitude 58-71 degrees N is a discrete exception to the hypothesis that solar UV radiation exposure, mediated by vitamin D, coheres with the latitude gradient seen for MS prevalence. Where UV radiation exposure is low in Norway,vitamin D sufficiency is maintained through a traditional diet providing vitamin D as well as marine omega-3 polyunsaturated fatty acids. This observation supports an environmental interaction between diet and latitude, with vitamin D as the common mediator. The potential roles of vitamin D, other environmental exposures, and genes in the complex aetiology of MS are discussed in this review., ((c) 2008 S. Karger AG, Basel)