| 1. |
- van Doormaal, Perry T. C., et al.
(författare)
-
The role of de novo mutations in the development of amyotrophic lateral sclerosis
- 2017
-
Ingår i: Human Mutation. - : John Wiley & Sons. - 1059-7794 .- 1098-1004. ; 38:11, s. 1534-1541
-
Tidskriftsartikel (refereegranskat)abstract
- The genetic basis combined with the sporadic occurrence of amyotrophic lateral sclerosis (ALS) suggests a role of de novo mutations in disease pathogenesis. Previous studies provided some evidence for this hypothesis; however, results were conflicting: no genes with recurrent occurring de novo mutations were identified and different pathways were postulated. In this study, we analyzed whole-exome data from 82 new patient-parents trios and combined it with the datasets of all previously published ALS trios (173 trios in total). The per patient de novo rate was not higher than expected based on the general population (P = 0.40). We showed that these mutations are not part of the previously postulated pathways, and gene-gene interaction analysis found no enrichment of interacting genes in this group (P = 0.57). Also, we were able to show that the de novo mutations in ALS patients are located in genes already prone for de novo mutations (P < 1 x 10(-15)). Although the individual effect of rare de novo mutations in specific genes could not be assessed, our results indicate that, in contrast to previous hypothesis, de novo mutations in general do not impose a major burden on ALS risk.
|
|
| 2. |
- Endo, Satoshi, et al.
(författare)
-
Instability of C154Y variant of aldo-keto reductase 1C3
- 2017
-
Ingår i: Chemico-Biological Interactions. - : Elsevier. - 0009-2797 .- 1872-7786. ; 276, s. 194-202
-
Tidskriftsartikel (refereegranskat)abstract
- Aldo-keto reductase (AKR) 1C3 is a cytosolic enzyme that metabolizes steroids, prostaglandins, toxic aldehydes and drugs. Recently, some nonsynonymous single nucleotide polymorphisms of AKR1C3 have been suggested to impact steroid and drug metabolism. In this study, we examined the effects of C154Y and L159V variants of AKR1C3 on stability and function of the enzyme. Both variants had been detected in patients with the neurodegenerative disease amyotrophic lateral sclerosis. Recombinant wild-type (WT), C154Y and L159V enzymes were similar in specific activity, but C154Y displayed much lower thermostability than WT and L159V. C154Y was inactivated by 10-min incubation at >25 °C, and about 90% of its activity was lost at 40 °C. Differential scanning fluorimetry revealed that Tm (thermal denaturation midpoint) of C154Y was lower than that of WT. In order to study the cause of thermosensitivity of C154Y, we prepared C154F and C154S mutant AKR1C3s. Like C154Y, C154F was highly sensitive to thermal inactivation, whereas C154S showed almost the same thermostability as WT. The C154F and C154Y variants induced secondary and tertiary structural changes in AKR1C3 at 40 °C as reflected by their altered circular dichroism and 8-anilinonaphthalene-1-sulfonate fluorescence characteristics. These results suggest that the replacement of C154 with a residue possessing a bulky aromatic side-chain impairs the folding of the α-helix containing C154 and its neighboring secondary structures, leading to low thermostability of AKR1C3. AKR1C3 metabolizes cytotoxic 4-oxo-2-nonenal into a less toxic metabolite, and overexpression of WT in HEK293 cells alleviated the 4-oxo-2-nonenal-induced cytotoxicity. In contrast, the overexpression of C154Y in the cells did not show such a significant protective effect, suggesting that C154Y is unstable in cells.
|
|
| 3. |
- Freischmidt, Axel, et al.
(författare)
-
Association of Mutations in TBK1 With Sporadic and Familial Amyotrophic Lateral Sclerosis and Frontotemporal Dementia
- 2017
-
Ingår i: JAMA Neurology. - : American Medical Association. - 2168-6149 .- 2168-6157. ; 74:1, s. 110-113
-
Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are related neurodegenerative syndromes that occur sporadically or have been associated with mostly dominant inheritance of mutations in more than 30 genes. A critical issue is whether all reported mutations are disease causing or are coincidental findings. In this review we analyze the pathogenicity of nonsynonymous variants in the newly discovered gene encoding TANK-binding kinase 1 (TBK1). The available data suggest that mutations in TBK1 that cause a 50% reduction of TBK1 protein levels are pathogenic. In most cases, the almost complete loss of expression of the mutated TBK1 allele is due to loss-of-function mutations creating a premature termination codon and the degradation of the mutated messenger RNA by nonsense-mediated messenger RNA decay. In addition, TBK1 protein levels reduced by 50% have been proven for specific in-frame deletions of 1 or several amino acids, probably due to increased degradation of the mutated protein. Evaluation of many of the TBK1 missense mutations found in patients with ALS or FTD is prevented by missing data demonstrating cosegregation of the variants and incomplete knowledge about the TBK1 functions relevant for neurodegeneration. These findings suggest that haploinsufficiency of TBK1 is causative for ALS and FTD regardless of the type of mutation. Evaluation of TBK1 variants that do not cause haploinsufficiency is not possible without data demonstrating cosegregation.
|
|
| 4. |
- Gorges, Martin, et al.
(författare)
-
Hypothalamic atrophy is related to body mass index and age at onset in amyotrophic lateral sclerosis
- 2017
-
Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 0022-3050 .- 1468-330X. ; 88:12, s. 1033-1041
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Our objective was to study the hypothalamic volume in a cohort of patients with amyotrophic lateral sclerosis (ALS) including symptomatic and presymptomatic ALS mutation carriers.Methods: High-resolution three-dimensional T1-weighted MRI datasets from 251 patients with sporadic ALS, 19 symptomatic and 32 presymptomatic ALS mutation carriers and 112 healthy controls (HC) were retrospectivally registered for manual delineation of the hypothalamus. The volume of the hypothalamus, in total or subdivided, was normalised to the intracranial volume and adjusted to age. Correlation analyses were performed with clinical and metabolic outcomes. Pathologically defined ALS stages were determined in vivo by diffusion tensor imaging (DTI).Results: We observed a severe atrophy of the hypothalamus both in patients with sporadic ALS (-21.8%, p<0.0001) and symptomatic ALS mutation carriers (-13.4%, p<0.001). The atrophy in patients with sporadic ALS was observed in both the anterior (-27.6% p<0.0001) and the posterior parts of the hypothalamus (-17.7%, p<0.0001). Notably, this atrophy was also observed in presymptomatic ALS mutation carriers (-15.5%, p<0.001) and was unrelated to whole brain volume atrophy or disease stage as assessed using DTI or functional status. Hypothalamic volume was correlated with body mass index (BMI) in patients with sporadic ALS (p=0.0434, Ρ=+0.1579), and this correlation was much stronger in patients with familial ALS (fALS) (p=0.0060, Ρ=+0.6053). Anterior hypothalamic volume was correlated with age at onset, but not with survival after MRI.Conclusions: Hypothalamus is atrophied in ALS, even in premorbid stages, and correlates with BMI, especially in fALS. Decreased anterior hypothalamic volume is associated with earlier onset of disease.
|
|
| 5. |
- Lange, Dale J., et al.
(författare)
-
Pyrimethamine Significantly Lowers Cerebrospinal Fluid Cu/Zn Superoxide Dismutase in Amyotrophic Lateral Sclerosis Patients with SOD1 Mutations
- 2017
-
Ingår i: Annals of Neurology. - : John Wiley & Sons. - 0364-5134 .- 1531-8249. ; 81:6, s. 837-848
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Cu/Zn superoxide dismutase (SOD1) reduction prolongs survival in SOD1-transgenic animal models. Pyrimethamine produces dose-dependent SOD1 reduction in cell culture systems. A previous phase 1 trial showed pyrimethamine lowers SOD1 levels in leukocytes in patients with SOD1 mutations. This study investigated whether pyrimethamine lowered SOD1 levels in the cerebrospinal fluid (CSF) in patients carrying SOD1 mutations linked to familial amyotrophic lateral sclerosis (fALS/SOD1). Methods: A multicenter (5 sites), open-label, 9-month-duration, dose-ranging study was undertaken to determine the safety and efficacy of pyrimethamine to lower SOD1 levels in the CSF in fALS/SOD1. All participants underwent 3 lumbar punctures, blood draw, clinical assessment of strength, motor function, quality of life, and adverse effect assessments. SOD1 levels were measured in erythrocytes and CSF. Pyrimethamine was measured in plasma and CSF. Appel ALS score, ALS Functional Rating Scale-Revised, and McGill Quality of Life Single-Item Scale were measured at screening, visit 6, and visit 9. Results: We enrolled 32 patients; 24 completed 6 visits (18 weeks), and 21 completed all study visits. A linear mixed effects model showed a significant reduction in CSF SOD1 at visit 6 (p<0.001) with a mean reduction of 13.5% (95% confidence interval [CI] 58.4-18.5) and at visit 9 (p<0.001) with a mean reduction of 10.5% (95% CI55.2-15.8). Interpretation: Pyrimethamine is safe and well tolerated in ALS. Pyrimethamine is capable of producing a significant reduction in total CSF SOD1 protein content in patients with ALS caused by different SOD1 mutations. Further long-term studies are warranted to assess clinical efficacy.
|
|
| 6. |
- Nordin, Angelica, et al.
(författare)
-
Sequence variations in C9orf72 downstream of the hexanucleotide repeat region and its effect on repeat-primed PCR interpretation : a large multinational screening study
- 2017
-
Ingår i: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. - : Informa UK Limited. - 2167-8421 .- 2167-9223. ; 18:3-4, s. 256-264
-
Tidskriftsartikel (refereegranskat)abstract
- A large GGGGCC-repeat expansion mutation (HREM) in C9orf72 is the most common known cause of ALS and FTD in European populations. Sequence variations immediately downstream of the HREM region have previously been observed and have been suggested to be one reason for difficulties in interpreting RP-PCR data. Our objective was to determine the properties of these sequence variations with regard to prevalence, the range of variation, and effect on disease prognosis. We screened a multi-national cohort (n = 6981) for the HREM and samples with deviant RP-PCR curves were identified. The deviant samples were subsequently sequenced to determine sequence alteration. Our results show that in the USA and European cohorts (n = 6508) 10.7% carried the HREM and 3% had a sequence variant, while no HREM or sequence variants were observed in the Japanese cohort (n = 473). Sequence variations were more common on HREM alleles; however, certain population specific variants were associated with a non-expanded allele. In conclusion, we identified 38 different sequence variants, most located within the first 50 bp downstream of the HREM region. Furthermore, the presence of an HREM was found to be coupled to a lower age of onset and a shorter disease survival, while sequence variation did not have any correlation with these parameters.
|
|
| 7. |
- Weber, Christian, et al.
(författare)
-
Existential decision-making in a fatal progressive disease : how much do legal and medical frameworks matter?
- 2017
-
Ingår i: BMC Palliative Care. - : Springer Science and Business Media LLC. - 1472-684X. ; 16
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Healthcare legislation in European countries is similar in many respects. Most importantly, the framework of informed consent determines that physicians have the duty to provide detailed information about available therapeutic options and that patients have the right to refuse measures that contradict their personal values. However, when it comes to end-of-life decision-making a number of differences exist in the more specific regulations of individual countries. These differences and how they might nevertheless impact patient’s choices will be addressed in the current debate.Main text: In this article we show how the legal and medical frameworks of Germany, Poland and Sweden differ with regard to end-of-life decisions for patients with a fatal progressive disease. Taking Amyotrophic Lateral Sclerosis (ALS) as an example, we systematically compare clinical guidelines and healthcare law, pointing out the country-specific differences most relevant for existential decision-making. A fictional case report discusses the implications of these differences for a patient with ALS living in either of the three countries. Patients with ALS in Germany, Poland and Sweden are confronted with a similar spectrum of treatment options. However, the analysis of the normative frameworks shows that the conditions for making existential decisions differ considerably in Germany, Poland and Sweden. Specifically, these differences concern (1) the legal status of advance directives, (2) the conditions under which life-sustaining therapies are started or withheld, and (3) the legal regulations on assisted dying.Conclusion: According to the presented data, regulations of terminating life-sustaining treatments and the framework of “informed consent” are quite differently understood and implemented in the legal setting of the three countries. It is possible, and even likely, that these differences in the legal and medical frameworks have a considerable influence on existential decisions of patients with ALS.
|
|
