ClinVar

Description

The m.15848A>G (p.T368A) variant in MT-CYB was reviewed by the Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel on July 10, 2023. There are no individuals or families with primary mitochondrial disease with this variant reported in the medical literature to our knowledge. This variant is present at varying frequencies in population databases. The frequency in the MITOMAP GenBank sequences in 38/59,389 (0.064%) spread over 13 top level (single letter) haplogroups with European, Asian, and African ancestry. The frequency of homoplasmic occurrences of this variant in the Helix dataset in 98/195,983 (0.050%), in addition to 10 heteroplasmic occurrences, spread over 15 top level haplogroups with European, Asian, and African ancestry. The frequency of homoplasmic occurrences in gnomAD v3.1.2 is 217/56,429 (0.385%) in addition to two heteroplasmic occurrences, spread over 13 top level haplogroups with European, Asian, and African ancestry. The overall frequency is notably higher in this database than in MITOMAP and Helix, with 185 of the gnomAD sequences categorized as Latin American and all in top level haplogroup A. Therefore, the frequency of this variant meets neither criteria for pathogenicity (<0.002%) nor benign status (>0.5%). The computational predictor APOGEE gives scores of 0.33 (“neutral”) in APOGEE1 and 0.0087 (“benign”) in APOGEE2 (Min=0, Max=1), predicting no impact on gene function (BP4). There are no cybrids, single fiber studies, or other functional assays reported for this variant to date. In summary, this variant meets criteria to be classified as uncertain significance for primary mitochondrial disease inherited in a mitochondrial manner. This classification was approved by the NICHD/NINDS U24 ClinGen Mitochondrial Disease Variant Curation Expert Panel on July 10, 2023. Mitochondrial DNA-specific ACMG/AMP criteria applied: BP4.