The shared ancestry between the C9orf72 hexanucleotide repeat expansion and intermediate-length alleles using haplotype sharing trees and HAPTK.

The C9orf72 hexanucleotide repeat expansion (HRE) is a common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The inheritance is autosomal dominant, but a high proportion of subjects with the mutation are simplex cases. One possible explanation is de novo expansions of unstable intermediate-length alleles (IAs).

hexanucleotide repeat allele tagging SNPs: Associations with ALS risk and longevity.

hexanucleotide repeat expansion is a common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The locus may harbor residual risk outside the hexanucleotide repeat expansion, but the evidence is conflicting. Here, we first compared 683 unrelated amyotrophic lateral sclerosis cases and 3,196 controls with Finnish ancestry to find best single nucleotide polymorphisms that tag the hexanucleotide repeat expansion and intermediate-length alleles.

New evidence on the association of occupation with amyotrophic lateral sclerosis: A register-based case-control study in Finland.

Objectives: Amyotrophic lateral sclerosis (ALS) is a serious neurodegenerative disease that usually leads to death within a few years from diagnosis. The risk factors for ALS are still largely unknown. However, it is assumed that environmental factors play a role in disease onset.

ALS patients in otorhinolaryngology: A retrospective study.

Objectives: Given its rarity and the lack of clear clinical markers, amyotrophic lateral sclerosis (ALS) remains a diagnostic challenge. Because bulbar-onset ALS (buALS) presents with impaired speech or swallowing, patients are often primarily referred to an otolaryngologist (ORL) or phoniatrician. The objectives of this retrospective cohort study were to analyze the role of ORLs and phoniatricians in ALS diagnostics and treatment and the potential diagnostic delay related to initial visit to aforementioned specialists.

ALS in Finland: Major Genetic Variants and Clinical Characteristics of Patients With and Without the Hexanucleotide Repeat Expansion.

Background And Objectives: To analyze the frequencies of major genetic variants and the clinical features in Finnish patients with amyotrophic lateral sclerosis (ALS) with or without the hexanucleotide repeat expansion.

Methods: A cohort of patients with motor neuron disease was recruited between 1993 and 2020 at the Helsinki University Hospital and 2 second-degree outpatient clinics in Helsinki. Finnish ancestry patients with ALS fulfilled the diagnosis according to the revised El Escorial criteria and the Awaji-criteria.

Association of Variants in the SPTLC1 Gene With Juvenile Amyotrophic Lateral Sclerosis.

Importance: Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.

Objective: To identify the genetic variants associated with juvenile ALS.

Design, Setting, And Participants: In this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation.

Home invasive mechanical ventilation in Finland in 2015-2019.

Introduction: The prevalence of long-term invasive mechanical ventilation tracheostomy in chronic respiratory insufficiency is largely unknown. We aimed to clarify prevalence and aetiology of the use of home invasive mechanical ventilation (HIMV) in Finland in 2015-2019.

Methods: Information on HIMV patients was collected yearly from all Finnish Hospital District patient registries between 1 January 2015 and 1 January 2019.

Carriership of two copies of C9orf72 hexanucleotide repeat intermediate-length alleles is a risk factor for ALS in the Finnish population.

The hexanucleotide repeat expansion in intron 1 of the C9orf72 gene causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. In addition to the effects of the pathogenic expansion, a role of intermediate-length alleles has been suggested in ALS, corticobasal degeneration and Parkinson's disease. Due to the rarity of intermediate-length alleles with over 20 repeats and the geographical variability in their frequency, large studies that account for population stratification are needed to elucidate their effects.

Oligogenic basis of sporadic ALS: The example of p.Ala90Val mutation.

Objective: To characterize the clinical and neuropathologic features of patients with amyotrophic lateral sclerosis (ALS) with the superoxide dismutase 1 () p.Ala90Val mutation, as well as the mutation frequency and the role of oligogenic mechanisms in disease penetrance.

Methods: An index patient with autopsy-proven ALS was discovered to have the p.

C9orf72 hexanucleotide repeat length in older population: normal variation and effects on cognition.

The hexanucleotide repeat expansion in C9orf72 is a common cause of amyotrophic lateral sclerosis/frontotemporal dementia and also rarely found in other psychiatric and neurodegenerative conditions. Alleles with >30 repeats are often considered an expansion, but the pathogenic repeat length threshold is still unclear. It is also unclear whether intermediate repeat length alleles (often defined either as 7-30 or 20-30 repeats) have clinically significant effects.

Discussing a serious illness with a patient and family.

Learning of a serious illness is unique news. Nothing certain can be known about how it will affect the hearer's outlook on the future before a conception is established about the hearer's expectations and how he/she has understood the issue. For example, a person who has been expecting muscle tension to be an explanation for back pain but hearing that a cancer metastasis is the underlying cause, will inevitably be in shock.

FGF21 is a biomarker for mitochondrial translation and mtDNA maintenance disorders.

Objective: To validate new mitochondrial myopathy serum biomarkers for diagnostic use.

Methods: We analyzed serum FGF21 (S-FGF21) and GDF15 from patients with (1) mitochondrial diseases and (2) nonmitochondrial disorders partially overlapping with mitochondrial disorder phenotypes. We (3) did a meta-analysis of S-FGF21 in mitochondrial disease and (4) analyzed S-Fgf21 and skeletal muscle Fgf21 expression in 6 mouse models with different muscle-manifesting mitochondrial dysfunctions.

[The pathogenesis of amyotrophic lateral sclerosis and frontal lobe dementia is unraveling: pathology of the nucleus and glutamate sensitivity].

The mechanisms of neurodegenerative diseases have begun to become unraveled, thanks to the progress in stem cell research. The repeat expansion in the C90RF72 gene was identified in 2011 as the most common genetic cause of both ALS and frontal lobe dementia. Only over a couple of years the disease mechanisms of this mutation have been revealed and treatment trials have already been conducted in nerve cell cultures differentiated from patients' stem cells.

Genome-wide analysis of the heritability of amyotrophic lateral sclerosis.

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.

Homozygosity analysis in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) may appear to be familial or sporadic, with recognised dominant and recessive inheritance in a proportion of cases. Sporadic ALS may be caused by rare homozygous recessive mutations. We studied patients and controls from the UK and a multinational pooled analysis of GWAS data on homozygosity in ALS to determine any potential recessive variant leading to the disease.

Frequency of the C9orf72 hexanucleotide repeat expansion in patients with amyotrophic lateral sclerosis and frontotemporal dementia: a cross-sectional study.

Background: We aimed to accurately estimate the frequency of a hexanucleotide repeat expansion in C9orf72 that has been associated with a large proportion of cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD).

Methods: We screened 4448 patients diagnosed with ALS (El Escorial criteria) and 1425 patients with FTD (Lund-Manchester criteria) from 17 regions worldwide for the GGGGCC hexanucleotide expansion using a repeat-primed PCR assay. We assessed familial disease status on the basis of self-reported family history of similar neurodegenerative diseases at the time of sample collection.

A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD.

The chromosome 9p21 amyotrophic lateral sclerosis-frontotemporal dementia (ALS-FTD) locus contains one of the last major unidentified autosomal-dominant genes underlying these common neurodegenerative diseases. We have previously shown that a founder haplotype, covering the MOBKL2b, IFNK, and C9ORF72 genes, is present in the majority of cases linked to this region. Here we show that there is a large hexanucleotide (GGGGCC) repeat expansion in the first intron of C9ORF72 on the affected haplotype.

Chromosome 9 ALS and FTD locus is probably derived from a single founder.

We and others have recently reported an association between amyotrophic lateral sclerosis (ALS) and single nucleotide polymorphisms on chromosome 9p21 in several populations. Here we show that the associated haplotype is the same in all populations and that several families previously shown to have genetic linkage to this region also share this haplotype. The most parsimonious explanation of these data are that there is a single founder for this form of disease.

Chromosome 9p21 in amyotrophic lateral sclerosis in Finland: a genome-wide association study.

Background: The genetic cause of amyotrophic lateral sclerosis (ALS) is not well understood. Finland is a well suited location for a genome-wide association study of ALS because the incidence of the disease is one of the highest in the world, and because the genetic homogeneity of the Finnish population enhances the ability to detect risk loci. We aimed to identify genetic risk factors for ALS in the Finnish population.

Magnetoencephalographic evidence of abnormal auditory processing in amyotrophic lateral sclerosis with bulbar signs.

Objective: Amyotrophic lateral sclerosis (ALS) is characterized by progressive motor neuron damage that gives rise to muscle denervation. Besides motor neuron damage, conscious auditory processing appears to be impaired in ALS, whereas it has remained ambiguous whether preceding automatic auditory processing is abnormal in ALS and specifically in ALS with bulbar signs.

Methods: Auditory evoked fields (AEFs) to monaurally presented frequent and infrequent tones with stimulus intervals of 500 and 2500 ms were recorded with magnetoencephalography (MEG) from 10 ALS patients having bulbar signs and from 10 age-matched healthy subjects.