Mitochondrial DNA (mtDNA) variants for gnomAD are now available for the first time! We have called mtDNA variants for 56,434 whole genome samples in the v3.1 release. This initial release includes population frequencies for 10,850 unique mtDNA variants defined at more than half of all mtDNA bases. The vast majority of variant calls (98%) are homoplasmic or near homoplasmic, whereas 2% are heteroplasmic. Variation in mitochondrial genomes contributes to many human diseases and has had unique value in the study of human evolutionary genetics. We hope that the addition of mtDNA to gnomAD will enable researchers to better understand the role of mtDNA variation in both health and disease states.
Previous gnomAD callsets have not included mtDNA variants because their properties do not fit the assumptions that we use with our nuclear variant calling pipeline. These properties include: