@article{79f0dc93e1d644468cd294a72a516c6e,
title = "C9orf72 hexanucleotide repeat length in older population: normal variation and effects on cognition",
abstract = "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. We determined the C9orf72 repeat length distribution in 3142 older Finns (aged 60–104 years). The longest nonexpanded allele was 45 repeats. We found 7–45 repeats in 1036/3142 (33%) individuals, 20–45 repeats in 56/3142 (1.8%), 30–45 repeats in 12/3142 (0.38%), and expansion (>45 repeats) in 6/3142 (0.19%). There was no apparent clustering of neurodegenerative or psychiatric diseases in individuals with 30–45 repeats indicating that 30–45 repeats are not pathogenic. None of the 6 expansion carriers had a diagnosis of amyotrophic lateral sclerosis/frontotemporal dementia but 4 had a diagnosis of a neurodegenerative or psychiatric disease. Intermediate length alleles (categorized as 7–45 and 20–45 repeats) did not associate with Alzheimer's disease or cognitive impairment.",
keywords = "Alzheimer's disease, C9orf72, Cohort studies, Dementia, Genetics",
author = "Karri Kaivola and Anna Kiviharju and Lilja Jansson and Ville Rantalainen and Eriksson, {Johan G.} and Strandberg, {Timo E.} and Hannu Laaksovirta and Renton, {Alan E.} and Traynor, {Bryan J.} and Liisa Myllykangas and Tienari, {Pentti J.}",
note = "Funding Information: The Helsinki Birth cohort study has been funded by The Academy of Finland , the Finnish Diabetes Research society , Folkh{\"a}lsan Research Foundation , Novo Nordisk Foundation , Finska L{\"a}kares{\"a}llskapet , Signe and Ane Gyllenberg Foundation , University of Helsinki , Ahokas Foundation , Juho Vainio Foundation , and Helsinki University Hospital . Funding Information: KK was funded by the Finnish Cultural Foundation and the UH Faculty of Medicine MD/PhD program. PJT has been supported by grants from the Sigrid Juselius Foundation and Helsinki University Hospital. This work was funded in part by the Intramural Research Program of the National Institute on Aging, National Institutes of Health (Z01-AG000949). LM has received funding from the Academy of Finland (grant number 294817). The Helsinki Birth cohort study has been funded by The Academy of Finland, the Finnish Diabetes Research society, Folkh{\"a}lsan Research Foundation, Novo Nordisk Foundation, Finska L{\"a}kares{\"a}llskapet, Signe and Ane Gyllenberg Foundation, University of Helsinki, Ahokas Foundation, Juho Vainio Foundation, and Helsinki University Hospital. The Helsinki Businessmen study has been funded by VTR-funding of the HUS/Helsinki University Hospital (TYH 2014245; 2015211, Sisu) and the Academy of Finland (grant number 311492). The authors are grateful to Professor Simon Mead (National Prion Clinic, MRC Prion Unit at the University College London) for sharing detailed C9orf72 allele distribution in the UK 1958 birth cohort. Funding Information: KK was funded by the Finnish Cultural Foundation and the UH Faculty of Medicine MD/PhD program. PJT has been supported by grants from the Sigrid Juselius Foundation and Helsinki University Hospital . This work was funded in part by the Intramural Research Program of the National Institute on Aging , National Institutes of Health ( Z01-AG000949 ). LM has received funding from the Academy of Finland (grant number 294817 ). Funding Information: The Helsinki Businessmen study has been funded by VTR-funding of the HUS/Helsinki University Hospital ( TYH 2014245; 2015211 , Sisu) and the Academy of Finland (grant number 311492 ). The authors are grateful to Professor Simon Mead (National Prion Clinic, MRC Prion Unit at the University College London) for sharing detailed C9orf72 allele distribution in the UK 1958 birth cohort. Publisher Copyright: {\textcopyright} 2019 The Author(s)",
year = "2019",
month = dec,
doi = "10.1016/j.neurobiolaging.2019.02.026",
language = "English",
volume = "84",
pages = "242.e7--242.e12",
journal = "Neurobiology of Aging",
issn = "0197-4580",
publisher = "Elsevier Inc.",
}