M-14487-T-C

Position:

• chrM-14487-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PP3 PM2_Supporting PS3_Moderate PS4 PP1_Moderate

This summary comes from the ClinGen Evidence Repository: The m.14487T>C (p.M63V) variant in MT-ND6 has been reported in at least 37 unrelated individuals with primary mitochondrial disease (PS4; PMIDs: 30741831, 33706792, 34223155, 32162843, 30461153, 30128709, 30095618, 28122886, 28429146, 27338358, 26530508, 23813926, 23463613, 24126373, 23847141, 23010433, 21364701, 21196529, 19062322, 18977334, 17535832, 16044424, 15625630, 15576045, 14595656, 14520668, 14684687, 20019223). Features seen in affected individuals include Leigh syndrome spectrum and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), as well as ataxia, dystonia, epilepsy, optic neuropathy, and ptosis. Heteroplasmy levels were variable in affected individuals as was age of onset (infancy to adulthood). This variant segregated with disease in multiple affected members in multiple families and several healthy family members had lower to undetectable levels of the variant (PP1_moderate; PMIDs: 14684687,17535832, 20019223, 24126373, 26530508, 28122886). This variant is absent in the GenBank dataset, Helix dataset, and gnomAD v3.1.2 (PM2_supporting). The computational predictor APOGEE gives a consensus rating of pathogenic with a score of 0.9 (Min=0, Max=1), which predicts a damaging effect on gene function (PP3). Cybrid studies have shown independent functional consequences (PS3_moderate) including almost undetectable rotenone-dependent oxygen consumption (PMID 14520668), an overproduction of reactive oxygen species (ROS, PMID 16337195), and decreased complex I activity corresponding with heteroplasmy levels as well as decreased levels of fully assembled complex I (PMID 14595656). In summary, this variant meets criteria to be classified as pathogenic 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 August 8, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID:32906214): PS4, PP1_moderate, PM2_supporting, PP3, PS3_moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA120627/MONDO:0044970/014

• Frequency: Mitomap GenBank: Absent
• Consequence: MT-ND6 ENST00000361681.2 missense
• Scores: Apogee2 Pathogenic 0.95
• Clinical Significance: Pathogenic reviewed by expert panel P:5 O:1 Dystonia-/-Leigh-Disease-/-ataxia-/-ptosis-/-epilepsy
• Conservation: PhyloP100: 3.75

Genes affected

MT-ND6 (HGNC:7462): (mitochondrially encoded NADH dehydrogenase 6) Enables NADH dehydrogenase (ubiquinone) activity. Involved in mitochondrial electron transport, NADH to ubiquinone and mitochondrial respiratory chain complex I assembly. Predicted to be located in mitochondrial inner membrane. Implicated in Leber hereditary optic neuropathy; Leigh disease; and spinal muscular atrophy with lower extremity predominante 2B. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MT-ND6	ENST00000361681.2	c.187A>G	p.Met63Val	missense_variant	1/1			P1

Frequencies

GnomAD4 exome Cov.: 0

We have no GnomAD4 genomes data on this position. Probably position not covered by the project.

Mitomap

Dystonia-/-Leigh-Disease-/-ataxia-/-ptosis-/-epilepsy

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Leigh syndrome Pathogenic:1 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine	Oct 17, 2019	The NC_012920.1:m.14487T>C (YP_003024037.1:p.Met63Val) variant in MTND6 gene is interpretated to be a Pathogenic variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes: PS1, PS3 -
not provided, no classification provided	literature only	GeneReviews	-	- -

Leigh syndrome due to mitochondrial complex I deficiency Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 01, 2003

- -

Mitochondrial disease Pathogenic:1

Pathogenic, reviewed by expert panel

curation

ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel, ClinGen

Aug 08, 2022

The m.14487T>C (p.M63V) variant in MT-ND6 has been reported in at least 37 unrelated individuals with primary mitochondrial disease (PS4; PMIDs: 30741831, 33706792, 34223155, 32162843, 30461153, 30128709, 30095618, 28122886, 28429146, 27338358, 26530508, 23813926, 23463613, 24126373, 23847141, 23010433, 21364701, 21196529, 19062322, 18977334, 17535832, 16044424, 15625630, 15576045, 14595656, 14520668, 14684687, 20019223). Features seen in affected individuals include Leigh syndrome spectrum and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS), as well as ataxia, dystonia, epilepsy, optic neuropathy, and ptosis. Heteroplasmy levels were variable in affected individuals as was age of onset (infancy to adulthood). This variant segregated with disease in multiple affected members in multiple families and several healthy family members had lower to undetectable levels of the variant (PP1_moderate; PMIDs: 14684687,17535832, 20019223, 24126373, 26530508, 28122886). This variant is absent in the GenBank dataset, Helix dataset, and gnomAD v3.1.2 (PM2_supporting). The computational predictor APOGEE gives a consensus rating of pathogenic with a score of 0.9 (Min=0, Max=1), which predicts a damaging effect on gene function (PP3). Cybrid studies have shown independent functional consequences (PS3_moderate) including almost undetectable rotenone-dependent oxygen consumption (PMID 14520668), an overproduction of reactive oxygen species (ROS, PMID 16337195), and decreased complex I activity corresponding with heteroplasmy levels as well as decreased levels of fully assembled complex I (PMID 14595656). In summary, this variant meets criteria to be classified as pathogenic 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 August 8, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): PS4, PP1_moderate, PM2_supporting, PP3, PS3_moderate. -

Striatal necrosis, bilateral, with dystonia Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 01, 2003

- -

Leber optic atrophy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Mendelics

May 04, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Apogee2	Pathogenic	0.95
Hmtvar	Pathogenic	0.87
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Benign	-0.50	T
DEOGEN2	Pathogenic	0.85	D
LIST_S2	Benign	0.86	D
MutationAssessor	Pathogenic	3.9	H
MutationTaster	Benign	0.99	N
PROVEAN	Uncertain	-4.0	D
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
GERP RS		4.0
Varity_R		0.81

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs199476109; hg19: chrM-14488;