Fig. 1

This study depicts the bidirectional MR framework utilized to examine the causal link between mtDNA copy number and NDs. Eight MR analyses were conducted to explore the reciprocal relationships between mtDNA copy number and several NDs. All employed genetic instruments were SNPs. AD, Alzheimer’s disease; PD, Parkinson’s disease; ALS, Amyotrophic lateral sclerosis; and MS, Multiple sclerosis; GWAS, genome-wide association studies; SNPs, single nucleotide polymorphisms