The Heritability of Amyotrophic Lateral Sclerosis in a Clinically Ascertained United States Research Registry (original) (raw)

An estimate of amyotrophic lateral sclerosis heritability using twin data

Journal of Neurology, Neurosurgery & Psychiatry, 2010

Background 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 worth while. Methods The authors performed two twin studies, one population-and one clinic-based. The authors used structural equation modelling to perform a meta-analysis of data from these studies and an existing twin study to estimate ALS heritability, and identified 171 twin pairs in which at least one twin had ALS. Results and discussion Five monozygotic twin pairs were concordant-affected, and 44 discordant-affected. No dizygotic twin pairs were concordant-affected, and 122 discordant-affected. The heritability of sporadic ALS was estimated as 0.61 (0.38 to 0.78) with the unshared environmental component 0.39 (0.22 to 0.62). ALS has a high heritability, and efforts to find causative genes should continue.

Genome-Wide Analysis of the Heritability of Amyotrophic Lateral Sclerosis

JAMA Neurology, 2014

IMPORTANCE Considerable advances have been made in our understanding of the genetics underlying amyotrophic lateral sclerosis (ALS). Nevertheless, for the majority of patients who receive a diagnosis of ALS, the role played by genetics is unclear. Further elucidation of the genetic architecture of this disease will help clarify the role of genetic variation in ALS populations.

Phenotypic and genotypic heterogeneity of dominantly inherited amyotrophic lateral sclerosis

Acta Neurologica Scandinavica, 1987

Twenty-seven cases of hereditary amyotrophic lateral sclerosis (ALS), belonging to 8 families, are reported. The analysis of the pedigrees suggests an autosomal dominant transmission, apparently with incomplete penetration. The mean age at onset of symptoms was 50.3 (SD 12.4) years. The mean duration of the disease was 31.2 (SD 20.4) months, ranging from 9 to 86. The median survival time was 24 months. The degree of variation of some quantitative characters, both within and among families, was statistically analyzed. The results support the hypothesis of a phenotypic and genetic heterogeneity of autosomal dominant transmitted ALS.

A Novel Locus for Familial Amyotrophic Lateral Sclerosis, on Chromosome 18q

The American Journal of Human Genetics, 2002

neurons in the cortex, brain stem, and spinal cord. Despite intensive research the basic pathophysiology of ALS remains unclear. Although most cases are sporadic, ∼10% of ALS cases are familial (FALS). Mutations in the Cu/ Zn superoxide dismutase (SOD1) gene cause ∼20% of FALS. The gene(s) responsible for the remaining 80% of FALS remain to be found. Using a large European kindred without SOD1 mutation and with classic autosomal dominant adult-onset ALS, we have identified a novel locus by performing a genome scan and linkage analysis. The maximum LOD score is 4.5 at recombination fraction 0.0, for polymorphism D18S39. Haplotype analysis has identified a 7.5-cM, 8-Mb region of chromosome 18q21, flanked by markers D18S846 and D18S1109, as a novel FALS locus.

Identification of Two Novel Loci for Dominantly Inherited Familial Amyotrophic Lateral Sclerosis

The American Journal of Human Genetics, 2003

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive, adult-onset motor neuron disease that arises as a dominantly inherited trait in ∼10% of ALS cases. Mutations in one gene, cytosolic Cu/Zn superoxide dismutase (SOD1), account for ∼25% of familial ALS (FALS) cases. We have performed a genetic linkage screen in 16 pedigrees with FALS with no evidence for mutations in the SOD1 gene and have identified novel ALS loci on chromosomes 16 and 20. The analysis of these genes will delineate pathways implicated as determinants of motor-neuron viability and provide insights into possible therapies for ALS. Much effort has been directed toward identification of gene defects that underlie the 10% of ALS cases that are inherited as dominant traits. To date, only one ALS gene has been identified (Rosen et al. 1993). It is striking that forced expression in mice (Gurney et al. 1994; Ripps et al. 1995; Wong et al. 1995) and rats (Nagai et al. 2001; Howland et al. 2002) of ALS-associated mutant forms of this gene, "SOD1" (MIM 147450), produces a rodent motor-neuron disorder that recapitulates most features of ALS. Two additional motor neuron-disease genes have been described recently, although their mutations are not associated with the phenotype of typical ALS

- Phenotypic heterogeneity of amyotrophic lateral sclerosis. a population based study

Background Different amyotrophic lateral sclerosis (ALS) phenotypes have been recognised, marked by a varying involvement of spinal and bulbar upper and lower motor neurons. However, the differential characteristics of these phenotypes are still largely unknown. Objective To define the epidemiology and outcome of ALS phenotypes in a population based setting. Methods All ALS cases incident in two Italian regions were prospectively collected from 1995 to 2004 in an epidemiological register. Cases were classified according to established ALS phenotypes: classic, bulbar, flail arm, flail leg, pyramidal, respiratory, pure lower motor neuron (PLMN) and pure upper motor neuron (PUMN). Results ALS phenotype were determined in 1332 out of 1351 incident patients (98.6%). Classic and bulbar phenotypes had similar mean annual incidence rates. Gender specific incidence rates showed a male preponderance in respiratory, flail arm, classic and PLMN phenotypes; in all other phenotypes, men and women had similar incidence rates. Age at onset was significantly lower in pyramidal, PLMN and PUMN phenotypes and higher in the bulbar phenotype. The best outcomes were observed in PUMN, pyramidal, PLMN and flail arm phenotypes and the worst in respiratory and bulbar phenotypes. Conclusions Our epidemiological findings suggest that ALS phenotypes carry distinctive and easily distinguishable clinical and prognostic characteristics, strongly related to a complex interplay between gender and age. The categorisation of ALS patients according to more homogenous clinical groups is relevant in identifying biological markers for ALS and should be considered for the design of clinical trials.