Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis

An individual’s genetics contributes to their risk of developing amyotrophic lateral sclerosis (ALS); however, there is still a large proportion of the heritability of ALS to be understood. Part of this missing heritability may lie in complex variants, such as the long interspersed element 1 (L1) re...

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Main Authors: Abigail L. Pfaff, Sulev Kõks
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Experimental Biology and Medicine
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Online Access:https://www.ebm-journal.org/articles/10.3389/ebm.2025.10575/full
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author Abigail L. Pfaff
Abigail L. Pfaff
Sulev Kõks
Sulev Kõks
author_facet Abigail L. Pfaff
Abigail L. Pfaff
Sulev Kõks
Sulev Kõks
author_sort Abigail L. Pfaff
collection DOAJ
description An individual’s genetics contributes to their risk of developing amyotrophic lateral sclerosis (ALS); however, there is still a large proportion of the heritability of ALS to be understood. Part of this missing heritability may lie in complex variants, such as the long interspersed element 1 (L1) retrotransposon, which have yet to be evaluated. The majority of L1 insertions in the human genome are no longer able to retrotranspose, but to date 279 retrotransposition-competent (RC) L1s have been reported. Many RC-L1s are polymorphic for their presence/absence; therefore, each individual will have a different number and complement of RC-L1s. These elements have been hypothesized to be involved in disease processes by multiple mechanisms such as somatic mutation by retrotransposition, the triggering of neuroinflammation and DNA damage. We hypothesize that L1s may influence disease development either through their effects on endogenous genes or through the properties that enable them to retrotranspose. Whole genome sequencing data from the New York Genome Center ALS consortium were used to characterize L1 variation identifying 2,803 polymorphic L1 elements and association analysis was performed in European individuals (ALS/ALS with other neurological disorder (ALSND) n = 2,653, controls n = 320). There were no individual L1 elements associated with disease, but we did identify a significant increase in the number of RC-L1s in ALS/ALSND genomes (p = 0.01) and the presence of ≥46 RC-L1s showed the most significant association (OR = 1.09 (1.02–1.16), p = 0.01) with disease. Analysis of individual L1s and their association with age at onset and survival identified one L1 whose presence was significantly associated with a lower age at onset (52.7 years) compared to homozygous absent individuals (59.2 years) (padj = 0.009). Our study has identified novel genetic factors for both disease risk and age at onset in ALS providing further evidence for the role of L1 retrotransposons in neurodegenerative diseases.
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spelling doaj-art-53cffee4791840eab55b80558c273d802025-08-20T02:31:59ZengFrontiers Media S.A.Experimental Biology and Medicine1535-36992025-06-0125010.3389/ebm.2025.1057510575Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosisAbigail L. Pfaff0Abigail L. Pfaff1Sulev Kõks2Sulev Kõks3Perron Institute for Neurological and Translational Science, Perth, WA, AustraliaPersonalised Medicine Centre, Health Futures Institute, Murdoch University, Murdoch, WA, AustraliaPerron Institute for Neurological and Translational Science, Perth, WA, AustraliaPersonalised Medicine Centre, Health Futures Institute, Murdoch University, Murdoch, WA, AustraliaAn individual’s genetics contributes to their risk of developing amyotrophic lateral sclerosis (ALS); however, there is still a large proportion of the heritability of ALS to be understood. Part of this missing heritability may lie in complex variants, such as the long interspersed element 1 (L1) retrotransposon, which have yet to be evaluated. The majority of L1 insertions in the human genome are no longer able to retrotranspose, but to date 279 retrotransposition-competent (RC) L1s have been reported. Many RC-L1s are polymorphic for their presence/absence; therefore, each individual will have a different number and complement of RC-L1s. These elements have been hypothesized to be involved in disease processes by multiple mechanisms such as somatic mutation by retrotransposition, the triggering of neuroinflammation and DNA damage. We hypothesize that L1s may influence disease development either through their effects on endogenous genes or through the properties that enable them to retrotranspose. Whole genome sequencing data from the New York Genome Center ALS consortium were used to characterize L1 variation identifying 2,803 polymorphic L1 elements and association analysis was performed in European individuals (ALS/ALS with other neurological disorder (ALSND) n = 2,653, controls n = 320). There were no individual L1 elements associated with disease, but we did identify a significant increase in the number of RC-L1s in ALS/ALSND genomes (p = 0.01) and the presence of ≥46 RC-L1s showed the most significant association (OR = 1.09 (1.02–1.16), p = 0.01) with disease. Analysis of individual L1s and their association with age at onset and survival identified one L1 whose presence was significantly associated with a lower age at onset (52.7 years) compared to homozygous absent individuals (59.2 years) (padj = 0.009). Our study has identified novel genetic factors for both disease risk and age at onset in ALS providing further evidence for the role of L1 retrotransposons in neurodegenerative diseases.https://www.ebm-journal.org/articles/10.3389/ebm.2025.10575/fullretrotransposonsL1amyotrophic lateral sclerosisneurodegenerationgenetics
spellingShingle Abigail L. Pfaff
Abigail L. Pfaff
Sulev Kõks
Sulev Kõks
Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
Experimental Biology and Medicine
retrotransposons
L1
amyotrophic lateral sclerosis
neurodegeneration
genetics
title Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
title_full Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
title_fullStr Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
title_full_unstemmed Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
title_short Retrotransposition-competent L1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
title_sort retrotransposition competent l1s are increased in the genomes of individuals with amyotrophic lateral sclerosis
topic retrotransposons
L1
amyotrophic lateral sclerosis
neurodegeneration
genetics
url https://www.ebm-journal.org/articles/10.3389/ebm.2025.10575/full
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AT sulevkoks retrotranspositioncompetentl1sareincreasedinthegenomesofindividualswithamyotrophiclateralsclerosis
AT sulevkoks retrotranspositioncompetentl1sareincreasedinthegenomesofindividualswithamyotrophiclateralsclerosis