Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2014
If citing, it is advised that you check and use the publisher's definitive version for pagination... more If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections.
If citing, it is advised that you check and use the publisher's definitive version for pagination... more If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections.
Exome sequencing is an effective strategy for identifying human disease genes. However, this meth... more Exome sequencing is an effective strategy for identifying human disease genes. However, this methodology is difficult in late-onset diseases where limited availability of DNA from informative family members prohibits comprehensive segregation analysis. To overcome this limitation, we performed an exome-wide rare variant burden analysis of 363 index cases with familial ALS (FALS). The results revealed an excess of patient variants within TUBA4A, the gene encoding the Tubulin, Alpha 4A protein. Analysis of a further 272 FALS cases and 5,510 internal controls confirmed the overrepresentation as statistically significant and replicable. Functional analyses revealed that TUBA4A mutants destabilize the microtubule network, diminishing its repolymerization capability. These results further emphasize the role of cytoskeletal defects in ALS and demonstrate the power of gene-based rare variant analyses in situations where causal genes cannot be identified through traditional segregation analy...
Objective-Substantial clinical, pathological and genetic overlap exists between amyotrophic later... more Objective-Substantial clinical, pathological and genetic overlap exists between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 inclusions have been found in both ALS and FTD cases (FTD-TDP). Recently, a repeat expansion in C9orf72 was identified as the causal variant in a proportion of ALS and FTD cases. We sought to identify additional evidence for a common genetic basis for the spectrum of ALS-FTD. Methods-We used published GWAS data of 4,377 ALS patients and 13,017 controls and 435 pathology-proven FTD-TDP cases and 1,414 controls for genotype imputation. Data were analyzed in a joint meta-analysis, by replicating topmost associated hits of one disease in the other, and by using a conservative rank products analysis, allocating equal weight to ALS and FTD-TDP sample sizes. Results-Meta-analysis identified 19 genome-wide significant single nucleotide polymorphisms (SNPs) at C9orf72 on chromosome 9p21.2 (lowest p=2.6×10 −12) and one SNP in UNC13A on chromosome 19p13.11 (p=1.0×10 −11) as shared susceptibility loci for ALS and FTD-TDP. Conditioning on the 9p21.2 genotype increased statistical significance at UNC13A. A third signal, on chromosome 8q24.13 at the SPG8 locus coding for strumpellin, (p=3.91×10 −7) was replicated in an independent cohort of 4,056 ALS patients and 3,958 controls (p=0.026; combined analysis p=1.01×10 −7).
The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mu... more The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mutations in the tau coding gene MAPT are a cause of frontotemporal dementia, and the H1/H1 genotype of MAPT, giving rise to higher tau expression levels, is associated with progressive supranuclear palsy, corticobasal degeneration, and Parkinson disease (PD). Furthermore, tau hyperphosphorylation and aggregation is a hallmark of Alzheimer disease (AD), and reducing endogenous tau has been reported to ameliorate cognitive impairment in a mouse model for AD. Tau hyperphosphorylation and aggregation have also been described in amyotrophic lateral sclerosis (ALS), both in human patients and in the mutant SOD1 mouse model for this disease. However, the precise role of tau in motor neuron degeneration remains uncertain. The possible association between ALS and the MAPT H1/H2 polymorphism was studied in 3,540 patients with ALS and 8,753 controls. Furthermore, the role of tau in the SOD1(G93A) mouse model for ALS was studied by deleting Mapt in this model. The MAPT genotype of the H1/H2 polymorphism did not influence ALS susceptibility (odds ratio = 1.08 [95% confidence interval 0.99-1.18], p = 0.08) and did not affect the clinical phenotype. Lowering tau levels in the SOD1(G93A) mouse failed to delay disease onset (p = 0.302) or to increase survival (p = 0.557). These findings suggest that the H1/H2 polymorphism in MAPT is not associated with human amyotrophic lateral sclerosis, and that lowering tau levels in the mutant SOD1 mouse does not affect the motor neuron degeneration in these animals.
Objective: We sought to define the significance of brachial amyotrophic diplegia (flail arm syndr... more Objective: We sought to define the significance of brachial amyotrophic diplegia (flail arm syndrome [FA]) and the pseudopolyneuritic variant (flail leg syndrome [FL]) of amyotrophic lateral sclerosis (ALS; motor neuron disease). Methods: We analyzed survival in clinic cohorts in London, UK (1,188 cases), and Melbourne, Australia (432 cases). Survival from disease onset was analyzed using the Kaplan-Meier method and Cox proportional hazards model. Results: In the London cohort, the FA syndrome represented 11% and the FL syndrome 6% of the sample. Median survival was 35 months for limb onset and 27 months for bulbar onset ALS, whereas this was 61 months for FA syndrome (p Ͻ 0.001) and 69 months for FL syndrome (p Ͻ 0.001). Five-year survival in this cohort was 8.8% for bulbar onset, 20% for limb onset, 52% for FA syndrome, and 64% for FL syndrome. The ratio of men to women was 4:1 in the FA group compared to 2:1 in other limb onset cases. Excluding lower motor neuron FA and FL cases, progressive muscular atrophy comprised 4% of the sample and had a prognosis similar to typical limb onset ALS. In the Melbourne cohort, median survival for limb onset ALS was 31 months, bulbar onset 27 months, FA syndrome 66 months (p Ͻ 0.001), and FL syndrome 71 months (p ϭ 0.001). Conclusions: The flail arm (FA) and flail leg (FL) syndromes had significantly better survival than typical amyotrophic lateral sclerosis (ALS) or progressive muscular atrophy cases that were not classified as FA or FL. Our findings underline the clinical and prognostic importance of the FA and FL variants of ALS. Neurology ® 2009;72:1087-1094 GLOSSARY ALS ϭ amyotrophic lateral sclerosis; CI ϭ confidence interval; DTR ϭ deep tendon reflex; FA ϭ flail arm syndrome; FL ϭ flail leg syndrome; LL ϭ lower limbs; LMN ϭ lower motor neuron; MND ϭ motor neuron disease; NIV ϭ noninvasive ventilation; PMA ϭ progressive muscular atrophy; UL ϭ upper limbs; UMN ϭ upper motor neuron. Amyotrophic lateral sclerosis (ALS) comprises several clinical phenotypes united by a common cellular and molecular pathology. 1 The three main clinical categories defined by Aran, Charcot, Duchenne, and others in the 19th century and which were subsequently shown to have both diagnostic and prognostic significance were progressive bulbar palsy (bulbar onset ALS), classic limb onset (Charcot) ALS, and a lower motor neuron form termed progressive muscular atrophy (PMA). 2-5 Prognostic factors in these forms of ALS have been delineated through clinic and population-based studies. 6,7 Bulbar onset tends to have a worse prognosis than limb onset, and both forms have a worse prognosis than PMA. 2,4-7 However, these three phenotypic categories do not fully capture the spectrum of clinical heterogeneity in ALS. This heterogeneity may contribute to diagnostic error and delay, and with the advent of large-scale whole genome studies that have the potential to identify genetic variants influencing both risk and phenotype,
Journal of Neurology, Neurosurgery & Psychiatry, 2010
Causative gene mutations have been identified in about 2% of those with amyotrophic lateral scler... more Causative gene mutations have been identified in about 2% of those with amyotrophic lateral sclerosis (ALS), often, but not always, when there is a strong family history. There is an assumption that there is a genetic component to all ALS, but genome-wide association studies have yet to produce a robustly replicated result. A definitive estimate of ALS heritability is therefore required to determine whether ongoing efforts to find susceptibility genes are worthwhile. We have performed two twin studies, one population and one clinic based. We used structural equation modelling to perform a meta-analysis of data from these studies and an existing twin study, to estimate ALS heritability. We identified 171 twin pairs in which at least one twin had ALS. Five monozygotic twin pairs were concordant affected and 44 discordant. No dizygotic twin pairs were concordant affected and 122 were discordant. The heritability of sporadic ALS was estimated as 0.61 (0.38, 0.78) with the unshared environmental component 0.39 (0.22, 0.62). ALS has high heritability and efforts to find causative genes should continue.
Four PLS patients underwent cerebral [(11)C]-flumazenil PET. They were compared firstly with a gr... more Four PLS patients underwent cerebral [(11)C]-flumazenil PET. They were compared firstly with a group of controls, then later directly with a group of sporadic ALS patients and a familial ALS group homozygous for the 'D90A' SOD1 gene mutation. There was a similar pattern of decreased binding in PLS patients when compared to controls as that seen in a previous study of sporadic ALS patients, supporting the concept that PLS is part of the same overall spectrum of MND. However, in direct group comparisons, both sporadic and homD90A ALS patients demonstrated relative decreases in anterior and orbito-frontal binding compared to PLS patients, suggesting that there may be differences in cortical vulnerability between phenotypic groups.
Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor n... more Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor neurons prolongs survival in rodent models of amyotrophic lateral sclerosis (ALS), while mice expressing reduced VEGF concentrations develop motor neuron degeneration reminiscent of ALS, raising the question whether VEGF contributes to the pathogenesis of ALS. An initial association study reported that VEGF haplotypes conferred increased susceptibility to ALS in humans, but later studies challenged this initial finding. A meta-analysis was undertaken to critically reappraise whether any of the three common VEGF gene variations (-2578C/A, -1154G/A and -634G/C) increase the risk of ALS. Over 7000 subjects from eight European and three American populations were included in the analysis. Pooled odds ratios were calculated using fixed-effects and random-effects models, and four potential sources of heterogeneity (location of disease onset, gender, age at disease onset and disease duration) were assessed. After correction, none of the genotypes or haplotypes was significantly associated with ALS. Subgroup analysis by gender revealed, however, that the -2578AA genotype, which lowers VEGF expression, increased the risk of ALS in males (OR = 1.46 males vs females; 95% CI = 1.19 to 1.80; p = 7.8 10E-5), even after correction for publication bias and multiple testing. This meta-analysis does not support the original conclusion that VEGF haplotypes increase the risk of ALS in humans, but the significant association of the low-VEGF -2578AA genotype with increased susceptibility to ALS in males reappraises the link between reduced VEGF concentrations and ALS, as originally revealed by the fortuitous mouse genetic studies.
Amyotrophic lateral sclerosis (ALS) is a spontaneous, relentlessly progressive motor neuron disea... more Amyotrophic lateral sclerosis (ALS) is a spontaneous, relentlessly progressive motor neuron disease, usually resulting in death from respiratory failure within 3 years. Variation in the genes SOD1 and TARDBP accounts for a small percentage of cases, and other genes have shown association in both candidate gene and genome-wide studies, but the genetic causes remain largely unknown. We have performed two independent parallel studies, both implicating the RNA polymerase II component, ELP3, in axonal biology and neuronal degeneration. In the first, an association study of 1884 microsatellite markers, allelic variants of ELP3 were associated with ALS in three human populations comprising 1483 people (P 5 1.96 3 10 29). In the second, an independent mutagenesis screen in Drosophila for genes important in neuronal communication and survival identified two different loss of function mutations, both in ELP3 (R475K and R456K). Furthermore, knock down of ELP3 protein levels using antisense morpholinos in zebrafish embryos resulted in dose-dependent motor axonal abnormalities [
Amyotrophic lateral sclerosis (ALS) is a severe clinical condition characterized by upper and low... more Amyotrophic lateral sclerosis (ALS) is a severe clinical condition characterized by upper and lower motor neuron degeneration for which there is no truly effective treatment. The absence of an effective treatment can be explained in part by the complex and heterogeneous genetic, biochemical, and clinical features of ALS. While ALS accounts for the majority of the motor neuron diseases, the recognition of disease variants and mimic syndromes may lead to further insights into possible causes for the generality of ALS. From a biochemical perspective, the process of motor neuron degeneration is complex and the multifactorial influences and potential biomarkers of ALS have never been assessed in the light of the clinical heterogeneity of ALS. Several genes and environmental influences have been suggested as possible risk factors of ALS. A better understanding of interactions between these risk factors, potential biomarkers and heterogeneous clinical features may lead to more clearly defined pathological profiles among individuals or groups of ALS patients and in turn lead to more focused therapeutic trials.
Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons with a median survi... more Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons with a median survival of 2 years. Most patients have no family history of amyotrophic lateral sclerosis, but current understanding of such diseases suggests there should be an increased risk to relatives. Furthermore, it is a common question to be asked by patients and relatives in clinic. We therefore set out to determine the risk of amyotrophic lateral sclerosis to first degree relatives of patients with sporadic amyotrophic lateral sclerosis attending a specialist clinic. Case records of patients with sporadic amyotrophic lateral sclerosis seen at a tertiary referral centre over a 16-year period were reviewed, and pedigree structures extracted. All individuals who had originally presented with sporadic amyotrophic lateral sclerosis, but who subsequently had an affected first degree relative, were identified. Calculations were age-adjusted using clinic population demographics. Probands (n = 1502), full siblings (n = 1622) and full offspring (n = 1545) were identified. Eight of the siblings and 18 offspring had developed amyotrophic lateral sclerosis. The unadjusted risk of amyotrophic lateral sclerosis over the observation period was 0.5% for siblings and 1.0% for offspring. Age information was available for 476 siblings and 824 offspring. For this subset, the crude incidence of amyotrophic lateral sclerosis was 0.11% per year (0.05-0.21%) in siblings and 0.11% per year (0.06-0.19%) in offspring, and the clinic age-adjusted incidence rate was 0.12% per year (0.04-0.21%) in siblings. By age 85, siblings were found to have an 8-fold increased risk of amyotrophic lateral sclerosis, in comparison to the background population. In practice, this means the risk of remaining unaffected by age 85 dropped from 99.7% to 97.6%. Relatives of people with sporadic amyotrophic lateral sclerosis have a small but definite increased risk of being affected.
Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2014
If citing, it is advised that you check and use the publisher's definitive version for pagination... more If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections.
If citing, it is advised that you check and use the publisher's definitive version for pagination... more If citing, it is advised that you check and use the publisher's definitive version for pagination, volume/issue, and date of publication details. And where the final published version is provided on the Research Portal, if citing you are again advised to check the publisher's website for any subsequent corrections.
Exome sequencing is an effective strategy for identifying human disease genes. However, this meth... more Exome sequencing is an effective strategy for identifying human disease genes. However, this methodology is difficult in late-onset diseases where limited availability of DNA from informative family members prohibits comprehensive segregation analysis. To overcome this limitation, we performed an exome-wide rare variant burden analysis of 363 index cases with familial ALS (FALS). The results revealed an excess of patient variants within TUBA4A, the gene encoding the Tubulin, Alpha 4A protein. Analysis of a further 272 FALS cases and 5,510 internal controls confirmed the overrepresentation as statistically significant and replicable. Functional analyses revealed that TUBA4A mutants destabilize the microtubule network, diminishing its repolymerization capability. These results further emphasize the role of cytoskeletal defects in ALS and demonstrate the power of gene-based rare variant analyses in situations where causal genes cannot be identified through traditional segregation analy...
Objective-Substantial clinical, pathological and genetic overlap exists between amyotrophic later... more Objective-Substantial clinical, pathological and genetic overlap exists between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP-43 inclusions have been found in both ALS and FTD cases (FTD-TDP). Recently, a repeat expansion in C9orf72 was identified as the causal variant in a proportion of ALS and FTD cases. We sought to identify additional evidence for a common genetic basis for the spectrum of ALS-FTD. Methods-We used published GWAS data of 4,377 ALS patients and 13,017 controls and 435 pathology-proven FTD-TDP cases and 1,414 controls for genotype imputation. Data were analyzed in a joint meta-analysis, by replicating topmost associated hits of one disease in the other, and by using a conservative rank products analysis, allocating equal weight to ALS and FTD-TDP sample sizes. Results-Meta-analysis identified 19 genome-wide significant single nucleotide polymorphisms (SNPs) at C9orf72 on chromosome 9p21.2 (lowest p=2.6×10 −12) and one SNP in UNC13A on chromosome 19p13.11 (p=1.0×10 −11) as shared susceptibility loci for ALS and FTD-TDP. Conditioning on the 9p21.2 genotype increased statistical significance at UNC13A. A third signal, on chromosome 8q24.13 at the SPG8 locus coding for strumpellin, (p=3.91×10 −7) was replicated in an independent cohort of 4,056 ALS patients and 3,958 controls (p=0.026; combined analysis p=1.01×10 −7).
The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mu... more The microtubule-associated protein tau is thought to play a pivotal role in neurodegeneration. Mutations in the tau coding gene MAPT are a cause of frontotemporal dementia, and the H1/H1 genotype of MAPT, giving rise to higher tau expression levels, is associated with progressive supranuclear palsy, corticobasal degeneration, and Parkinson disease (PD). Furthermore, tau hyperphosphorylation and aggregation is a hallmark of Alzheimer disease (AD), and reducing endogenous tau has been reported to ameliorate cognitive impairment in a mouse model for AD. Tau hyperphosphorylation and aggregation have also been described in amyotrophic lateral sclerosis (ALS), both in human patients and in the mutant SOD1 mouse model for this disease. However, the precise role of tau in motor neuron degeneration remains uncertain. The possible association between ALS and the MAPT H1/H2 polymorphism was studied in 3,540 patients with ALS and 8,753 controls. Furthermore, the role of tau in the SOD1(G93A) mouse model for ALS was studied by deleting Mapt in this model. The MAPT genotype of the H1/H2 polymorphism did not influence ALS susceptibility (odds ratio = 1.08 [95% confidence interval 0.99-1.18], p = 0.08) and did not affect the clinical phenotype. Lowering tau levels in the SOD1(G93A) mouse failed to delay disease onset (p = 0.302) or to increase survival (p = 0.557). These findings suggest that the H1/H2 polymorphism in MAPT is not associated with human amyotrophic lateral sclerosis, and that lowering tau levels in the mutant SOD1 mouse does not affect the motor neuron degeneration in these animals.
Objective: We sought to define the significance of brachial amyotrophic diplegia (flail arm syndr... more Objective: We sought to define the significance of brachial amyotrophic diplegia (flail arm syndrome [FA]) and the pseudopolyneuritic variant (flail leg syndrome [FL]) of amyotrophic lateral sclerosis (ALS; motor neuron disease). Methods: We analyzed survival in clinic cohorts in London, UK (1,188 cases), and Melbourne, Australia (432 cases). Survival from disease onset was analyzed using the Kaplan-Meier method and Cox proportional hazards model. Results: In the London cohort, the FA syndrome represented 11% and the FL syndrome 6% of the sample. Median survival was 35 months for limb onset and 27 months for bulbar onset ALS, whereas this was 61 months for FA syndrome (p Ͻ 0.001) and 69 months for FL syndrome (p Ͻ 0.001). Five-year survival in this cohort was 8.8% for bulbar onset, 20% for limb onset, 52% for FA syndrome, and 64% for FL syndrome. The ratio of men to women was 4:1 in the FA group compared to 2:1 in other limb onset cases. Excluding lower motor neuron FA and FL cases, progressive muscular atrophy comprised 4% of the sample and had a prognosis similar to typical limb onset ALS. In the Melbourne cohort, median survival for limb onset ALS was 31 months, bulbar onset 27 months, FA syndrome 66 months (p Ͻ 0.001), and FL syndrome 71 months (p ϭ 0.001). Conclusions: The flail arm (FA) and flail leg (FL) syndromes had significantly better survival than typical amyotrophic lateral sclerosis (ALS) or progressive muscular atrophy cases that were not classified as FA or FL. Our findings underline the clinical and prognostic importance of the FA and FL variants of ALS. Neurology ® 2009;72:1087-1094 GLOSSARY ALS ϭ amyotrophic lateral sclerosis; CI ϭ confidence interval; DTR ϭ deep tendon reflex; FA ϭ flail arm syndrome; FL ϭ flail leg syndrome; LL ϭ lower limbs; LMN ϭ lower motor neuron; MND ϭ motor neuron disease; NIV ϭ noninvasive ventilation; PMA ϭ progressive muscular atrophy; UL ϭ upper limbs; UMN ϭ upper motor neuron. Amyotrophic lateral sclerosis (ALS) comprises several clinical phenotypes united by a common cellular and molecular pathology. 1 The three main clinical categories defined by Aran, Charcot, Duchenne, and others in the 19th century and which were subsequently shown to have both diagnostic and prognostic significance were progressive bulbar palsy (bulbar onset ALS), classic limb onset (Charcot) ALS, and a lower motor neuron form termed progressive muscular atrophy (PMA). 2-5 Prognostic factors in these forms of ALS have been delineated through clinic and population-based studies. 6,7 Bulbar onset tends to have a worse prognosis than limb onset, and both forms have a worse prognosis than PMA. 2,4-7 However, these three phenotypic categories do not fully capture the spectrum of clinical heterogeneity in ALS. This heterogeneity may contribute to diagnostic error and delay, and with the advent of large-scale whole genome studies that have the potential to identify genetic variants influencing both risk and phenotype,
Journal of Neurology, Neurosurgery & Psychiatry, 2010
Causative gene mutations have been identified in about 2% of those with amyotrophic lateral scler... more Causative gene mutations have been identified in about 2% of those with amyotrophic lateral sclerosis (ALS), often, but not always, when there is a strong family history. There is an assumption that there is a genetic component to all ALS, but genome-wide association studies have yet to produce a robustly replicated result. A definitive estimate of ALS heritability is therefore required to determine whether ongoing efforts to find susceptibility genes are worthwhile. We have performed two twin studies, one population and one clinic based. We used structural equation modelling to perform a meta-analysis of data from these studies and an existing twin study, to estimate ALS heritability. We identified 171 twin pairs in which at least one twin had ALS. Five monozygotic twin pairs were concordant affected and 44 discordant. No dizygotic twin pairs were concordant affected and 122 were discordant. The heritability of sporadic ALS was estimated as 0.61 (0.38, 0.78) with the unshared environmental component 0.39 (0.22, 0.62). ALS has high heritability and efforts to find causative genes should continue.
Four PLS patients underwent cerebral [(11)C]-flumazenil PET. They were compared firstly with a gr... more Four PLS patients underwent cerebral [(11)C]-flumazenil PET. They were compared firstly with a group of controls, then later directly with a group of sporadic ALS patients and a familial ALS group homozygous for the 'D90A' SOD1 gene mutation. There was a similar pattern of decreased binding in PLS patients when compared to controls as that seen in a previous study of sporadic ALS patients, supporting the concept that PLS is part of the same overall spectrum of MND. However, in direct group comparisons, both sporadic and homD90A ALS patients demonstrated relative decreases in anterior and orbito-frontal binding compared to PLS patients, suggesting that there may be differences in cortical vulnerability between phenotypic groups.
Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor n... more Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor neurons prolongs survival in rodent models of amyotrophic lateral sclerosis (ALS), while mice expressing reduced VEGF concentrations develop motor neuron degeneration reminiscent of ALS, raising the question whether VEGF contributes to the pathogenesis of ALS. An initial association study reported that VEGF haplotypes conferred increased susceptibility to ALS in humans, but later studies challenged this initial finding. A meta-analysis was undertaken to critically reappraise whether any of the three common VEGF gene variations (-2578C/A, -1154G/A and -634G/C) increase the risk of ALS. Over 7000 subjects from eight European and three American populations were included in the analysis. Pooled odds ratios were calculated using fixed-effects and random-effects models, and four potential sources of heterogeneity (location of disease onset, gender, age at disease onset and disease duration) were assessed. After correction, none of the genotypes or haplotypes was significantly associated with ALS. Subgroup analysis by gender revealed, however, that the -2578AA genotype, which lowers VEGF expression, increased the risk of ALS in males (OR = 1.46 males vs females; 95% CI = 1.19 to 1.80; p = 7.8 10E-5), even after correction for publication bias and multiple testing. This meta-analysis does not support the original conclusion that VEGF haplotypes increase the risk of ALS in humans, but the significant association of the low-VEGF -2578AA genotype with increased susceptibility to ALS in males reappraises the link between reduced VEGF concentrations and ALS, as originally revealed by the fortuitous mouse genetic studies.
Amyotrophic lateral sclerosis (ALS) is a spontaneous, relentlessly progressive motor neuron disea... more Amyotrophic lateral sclerosis (ALS) is a spontaneous, relentlessly progressive motor neuron disease, usually resulting in death from respiratory failure within 3 years. Variation in the genes SOD1 and TARDBP accounts for a small percentage of cases, and other genes have shown association in both candidate gene and genome-wide studies, but the genetic causes remain largely unknown. We have performed two independent parallel studies, both implicating the RNA polymerase II component, ELP3, in axonal biology and neuronal degeneration. In the first, an association study of 1884 microsatellite markers, allelic variants of ELP3 were associated with ALS in three human populations comprising 1483 people (P 5 1.96 3 10 29). In the second, an independent mutagenesis screen in Drosophila for genes important in neuronal communication and survival identified two different loss of function mutations, both in ELP3 (R475K and R456K). Furthermore, knock down of ELP3 protein levels using antisense morpholinos in zebrafish embryos resulted in dose-dependent motor axonal abnormalities [
Amyotrophic lateral sclerosis (ALS) is a severe clinical condition characterized by upper and low... more Amyotrophic lateral sclerosis (ALS) is a severe clinical condition characterized by upper and lower motor neuron degeneration for which there is no truly effective treatment. The absence of an effective treatment can be explained in part by the complex and heterogeneous genetic, biochemical, and clinical features of ALS. While ALS accounts for the majority of the motor neuron diseases, the recognition of disease variants and mimic syndromes may lead to further insights into possible causes for the generality of ALS. From a biochemical perspective, the process of motor neuron degeneration is complex and the multifactorial influences and potential biomarkers of ALS have never been assessed in the light of the clinical heterogeneity of ALS. Several genes and environmental influences have been suggested as possible risk factors of ALS. A better understanding of interactions between these risk factors, potential biomarkers and heterogeneous clinical features may lead to more clearly defined pathological profiles among individuals or groups of ALS patients and in turn lead to more focused therapeutic trials.
Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons with a median survi... more Amyotrophic lateral sclerosis is a neurodegenerative disease of motor neurons with a median survival of 2 years. Most patients have no family history of amyotrophic lateral sclerosis, but current understanding of such diseases suggests there should be an increased risk to relatives. Furthermore, it is a common question to be asked by patients and relatives in clinic. We therefore set out to determine the risk of amyotrophic lateral sclerosis to first degree relatives of patients with sporadic amyotrophic lateral sclerosis attending a specialist clinic. Case records of patients with sporadic amyotrophic lateral sclerosis seen at a tertiary referral centre over a 16-year period were reviewed, and pedigree structures extracted. All individuals who had originally presented with sporadic amyotrophic lateral sclerosis, but who subsequently had an affected first degree relative, were identified. Calculations were age-adjusted using clinic population demographics. Probands (n = 1502), full siblings (n = 1622) and full offspring (n = 1545) were identified. Eight of the siblings and 18 offspring had developed amyotrophic lateral sclerosis. The unadjusted risk of amyotrophic lateral sclerosis over the observation period was 0.5% for siblings and 1.0% for offspring. Age information was available for 476 siblings and 824 offspring. For this subset, the crude incidence of amyotrophic lateral sclerosis was 0.11% per year (0.05-0.21%) in siblings and 0.11% per year (0.06-0.19%) in offspring, and the clinic age-adjusted incidence rate was 0.12% per year (0.04-0.21%) in siblings. By age 85, siblings were found to have an 8-fold increased risk of amyotrophic lateral sclerosis, in comparison to the background population. In practice, this means the risk of remaining unaffected by age 85 dropped from 99.7% to 97.6%. Relatives of people with sporadic amyotrophic lateral sclerosis have a small but definite increased risk of being affected.
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