† We have standardized our variant notation to follow the 3' rule of HGVS (see their statement below). But for your reference, we also show the alternative notation, if previously reported, with position in red.

Quote from HGVS: "For deletions, duplications and insertions the most 3' position possible is arbitrarily assigned to have been changed. This rule also applies to variants in single residue stretches (mono-nucleotide or amino acid) or tandem repeats."

* The current GB frequency data is derived from two sets of human mitochondrial sequences from GenBank: 61,134 full length (FL) sequences (>15.4 kbp) and 81,124 short, control region (CR) containing sequences (0.4-1.6 kbp). By default the frequencies shown are from the FL set; where appropriate, frequencies from the CR set are also listed. For more details about our current GenBank sequence sets, please visit the GenBank Frequency Info page.

‡ High Frequency Haplogroups:

Variants found in haplogroups at 50% or higher are marked with . You may click a flagged link to see the high-scoring haplogroups. For detailed info about the high frequency haplogroup flag, please check the calculation criteria.

‡‡ gnomAD v3.1 Frequency:

The current haplogroup lineage distribution of gnomAD's 56434 sequences is N: 70%; L: 25%; M: 5%.

• The Genome Aggregation Database (gnomAD) aggregates exome and genome sequencing data from a wide variety of large-scale sequencing projects. It is available at https://gnomad.broadinstitute.org/. The mitochondrial DNA data shared here is from gnomAD v3.1, with their permission.
• Homoplasmic counts are used in the main table for comparison with Mitomap. GnomAD also provides heteroplasmy data down to a 10% cutoff.
• A count of "NR" indicates No Record in the database.
• Please be aware of the relatively low representation of lineage M ("Asian") haplogroups when comparing to other datasets.

‡‡‡ Helix Frequency:

The current haplogroup lineage distribution of Helix's 195893 sequences is N: 91%; L+M: 9%.

• The Helix population database is a variant catalog from ~196,000 buccal swab sequences primarily from ancestry services or broad general population surveys. The Helix data is reported with permission from Bolze et al. 2020, bioRxiv 798264 (see the article linked above).
• Homoplasmic counts are used in the main table for comparison with Mitomap. Helix also provides heteroplasmy data down to a ~1% cutoff (lowest=0.7%).
• A count of "NR" indicates No Record in the database.
• Due to privacy agreements, individual sequences are not publicly available and haplogroups are only reported at the top single-letter level (A-K, L0-L6, M-Z).
• Please be aware of the extremely high lineage N ("Eurasian") haplogroups when comparing to other datasets. Mitomap's estimation of the N, L, and M lineage distribution in Helix is 91.2%, 4.2%, and 4.6%, respectively.

^◊ New: As a member of the mtDNA Variant Curation Expert Panel for ClinGen, we are adding the calculated ClinGen pathogenicity ratings after VCEP curation. This will be shown in brackets in the Mitomap Status column, for example, "Reported [VUS^◊]", "Cfrm [LP^◊]", etc. The following abbreviations are used: B, Benign; LB, Likely Benign; VUS, Variant of Uncertain Significance; LP, Likely Pathogenic; P Pathogenic. The criteria used in the ClinGen curations may be found in McCormick et al, 2020, DOI: 10.1002/humu.24107. Note that the ClinGen scoring is quite stringent and gives fewer points than Mitomap does for many types of evidence, e.g., cybrid & other functional studies, in-silico tools, absence in large databases, heteroplasmy, de-novo requirements, and case numbers.

† MitoTIP:

• confirmed pathogenic
• likely pathogenic
• possibly pathogenic
• possibly benign
• likely benign
• frequency alert

For information about the predictive MitoTIP scoring for tRNA variants, please see MitoTIP Info.