We’re excited to announce the addition of mitochondrial genome (mtDNA) constraint metrics to gnomAD, developed using data from over 56,000 individuals in gnomAD v4.1^1,2. These new metrics are designed to identify regions of the mtDNA under strong selective pressure that are thus most likely to harbor functionally important and disease-associated variants. The gnomAD browser now features mitochondrial gene constraint and regional constraint metrics.