| Title: | GWAS and ExWAS of blood mitochondrial DNA copy number identifies 71 loci and highlights a potential causal role in dementia |
| Journal: | eLife |
| Published: | 13 Jan 2022 |
| Pubmed: | https://pubmed.ncbi.nlm.nih.gov/35023831/ |
| DOI: | https://doi.org/10.7554/elife.70382 |
Publication 13846
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Abstract
Background: Mitochondrial DNA copy number (mtDNA-CN) is an accessible blood-based measurement believed to capture underlying mitochondrial (MT) function. The specific biological processes underpinning its regulation, and whether those processes are causative for disease, is an area of active investigation.</p>
Methods: We developed a novel method for array-based mtDNA-CN estimation suitable for biobank-scale studies, called 'automatic mitochondrial copy (AutoMitoC).' We applied AutoMitoC to 395,781 UKBiobank study participants and performed genome- and exome-wide association studies, identifying novel common and rare genetic determinants. Finally, we performed two-sample Mendelian randomization to assess whether genetically low mtDNA-CN influenced select MT phenotypes.</p>
Results: Overall, genetic analyses identified 71 loci for mtDNA-CN, which implicated several genes involved in rare mtDNA depletion disorders, deoxynucleoside triphosphate (dNTP) metabolism, and the MT central dogma. Rare variant analysis identified SAMHD1 mutation carriers as having higher mtDNA-CN (beta = 0.23 SDs; 95% CI, 0.18-0.29; p=2.6 × 10-19), a potential therapeutic target for patients with mtDNA depletion disorders, but at increased risk of breast cancer (OR = 1.91; 95% CI, 1.52-2.40; p=2.7 × 10-8). Finally, Mendelian randomization analyses suggest a causal effect of low mtDNA-CN on dementia risk (OR = 1.94 per 1 SD decrease in mtDNA-CN; 95% CI, 1.55-2.32; p=7.5 × 10-4).</p>
Conclusions: Altogether, our genetic findings indicate that mtDNA-CN is a complex biomarker reflecting specific MT processes related to mtDNA regulation, and that these processes are causally related to human diseases.</p>
Funding: No funds supported this specific investigation. Awards and positions supporting authors include: Canadian Institutes of Health Research (CIHR) Frederick Banting and Charles Best Canada Graduate Scholarships Doctoral Award (MC, PM); CIHR Post-Doctoral Fellowship Award (RM); Wellcome Trust Grant number: 099313/B/12/A; Crasnow Travel Scholarship; Bongani Mayosi UCT-PHRI Scholarship 2019/2020 (TM); Wellcome Trust Health Research Board Irish Clinical Academic Training (ICAT) Programme Grant Number: 203930/B/16/Z (CJ); European Research Council COSIP Grant Number: 640580 (MO); E.J. Moran Campbell Internal Career Research Award (MP); CISCO Professorship in Integrated Health Systems and Canada Research Chair in Genetic and Molecular Epidemiology (GP).</p>
17 Keywords
- Adult
- Aged
- Biomarkers
- DNA Copy Number Variations
- DNA, Mitochondrial
- Dementia
- Exome Sequencing
- Female
- Gene Dosage
- Genome-Wide Association Study
- Humans
- Male
- Mendelian Randomization Analysis
- Middle Aged
- Mitochondria
- Phenotype
- United Kingdom
16 Authors
- Michael Chong
- Pedrum Mohammadi-Shemirani
- Nicolas Perrot
- Walter Nelson
- Robert Morton
- Sukrit Narula
- Ricky Lali
- Irfan Khan
- Mohammad Khan
- Conor Judge
- Tafadzwa Machipisa
- Nathan Cawte
- Martin O'Donnell
- Marie Pigeyre
- Loubna Akhabir
- Guillaume Paré
1 Application
| Application ID | Title |
|---|---|
| 15255 | Identification of the shared biological and sociodemographic factors underlying cardiovascular disease and dementia risk |
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