chrM-13042-G-A

Position:

• chrM-13042-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PP3 PM2_Supporting PS4_Moderate PP1_Moderate

This summary comes from the ClinGen Evidence Repository: The m.13042G>A (p.A236T) variant in MT-ND5 has been reported in six unrelated individuals with primary mitochondrial disease with onset ranging from the first year of life to adulthood; and features variably consistent CPEO, LHON, MERRF/MELAS, Leigh-like syndrome (PS4_moderate; PMIDs: 15767514; 17400793; 31996177; 16816025). This variant segregated with disease in a family with LHON as the proband's heteroplasmy was 41% in urine and his affected sister had the variant present at 39% in urine and 91% in muscle. There were unaffected sisters (heteroplasmy levels of 4% and 20% in urine) as well as an unaffected brother with the variant present at 43% urine. In another family, this variant segregated with Leigh syndrome in the proband (heteroplasmy level in in blood was 77%, in muscle was 84%, in fibroblasts was 86%); the healthy mother harbored the variant in hair (25%) and blood (11%); and the proband’s maternal grandmother was found to have the variant at < 2% in blood and between 4-6% in muscle (PP1_moderate, PMIDs: 16816025 17400793). There are no reports of confirmed de novo occurrences to our knowledge. This variant is absent in the Helix dataset and gnomAD v3.1.2, and there is only one occurrence in the GenBank dataset (PM2_supporting). The computational predictor APOGEE gives a consensus rating of pathogenic with a score of 0.85 (Min=0, Max=1), which predicts a damaging effect on gene function (PP3). There are no cybrids, single fiber studies, or other functional assays reported on this variant. In summary, this variant meets criteria to be classified as likely pathogenic for primary mitochondrial disease inherited in a mitochondrial manner. This classification was approved by the NICHD/NINDS U24 Mitochondrial Disease Variant Curation Expert Panel on June 13, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID:32906214): PS4_moderate, PP1_moderate, PP3, PM2_supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA120633/MONDO:0044970/014

• Frequency: Mitomap GenBank: Absent
• Consequence: MT-ND5 ENST00000361567.2 missense
• Scores: Apogee2 Pathogenic 0.89
• Clinical Significance: Likely pathogenic reviewed by expert panel P:6 O:1 Optic-neuropathy/-retinopathy/-LD
• Conservation: PhyloP100: 7.46

Genes affected

MT-ND5 (HGNC:7461): (mitochondrially encoded NADH dehydrogenase 5) Enables NADH dehydrogenase (ubiquinone) activity. Involved in mitochondrial electron transport, NADH to ubiquinone and mitochondrial respiratory chain complex I assembly. Part of mitochondrial respiratory chain complex I. Implicated in Leber hereditary optic neuropathy; Leigh disease; and MELAS syndrome. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP1: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MT-ND5	ENST00000361567.2	c.706G>A	p.Ala236Thr	missense_variant	1/1			ENSP00000354813	P1

Frequencies

GnomAD4 exome Cov.: 0

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

Mitomap

Optic-neuropathy/-retinopathy/-LD

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:6 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

MELAS syndrome Pathogenic:2 Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 01, 2007	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	3billion	-	The variant is not observed in the gnomAD v2.1.1 dataset. Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000009703). Should be validated by an alternate clinical test Therefore, this variant is classified as Likely pathogenic according to the recommendation of ACMG/AMP guideline. -

MERRF syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 01, 2007

- -

Leigh syndrome due to mitochondrial complex I deficiency Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 01, 2007

- -

Mitochondrial disease Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

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

Jun 30, 2022

The m.13042G>A (p.A236T) variant in MT-ND5 has been reported in six unrelated individuals with primary mitochondrial disease with onset ranging from the first year of life to adulthood; and features variably consistent CPEO, LHON, MERRF/MELAS, Leigh-like syndrome (PS4_moderate; PMIDs: 15767514; 17400793; 31996177; 16816025). This variant segregated with disease in a family with LHON as the proband's heteroplasmy was 41% in urine and his affected sister had the variant present at 39% in urine and 91% in muscle. There were unaffected sisters (heteroplasmy levels of 4% and 20% in urine) as well as an unaffected brother with the variant present at 43% urine. In another family, this variant segregated with Leigh syndrome in the proband (heteroplasmy level in in blood was 77%, in muscle was 84%, in fibroblasts was 86%); the healthy mother harbored the variant in hair (25%) and blood (11%); and the proband’s maternal grandmother was found to have the variant at < 2% in blood and between 4-6% in muscle (PP1_moderate, PMIDs: 16816025 17400793). There are no reports of confirmed de novo occurrences to our knowledge. This variant is absent in the Helix dataset and gnomAD v3.1.2, and there is only one occurrence in the GenBank dataset (PM2_supporting). The computational predictor APOGEE gives a consensus rating of pathogenic with a score of 0.85 (Min=0, Max=1), which predicts a damaging effect on gene function (PP3). There are no cybrids, single fiber studies, or other functional assays reported on this variant. In summary, this variant meets criteria to be classified as likely pathogenic for primary mitochondrial disease inherited in a mitochondrial manner. This classification was approved by the NICHD/NINDS U24 Mitochondrial Disease Variant Curation Expert Panel on June 13, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): PS4_moderate, PP1_moderate, PP3, PM2_supporting. -

Leber optic atrophy Pathogenic: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.13042G>A (YP_003024036.1:p.Ala236Thr) variant in MTND5 gene is interpretated to be a Pathogenic variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes: PS1, PM8, PM9, PM10 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Apogee2	Pathogenic	0.89
Hmtvar	Pathogenic	0.78
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Uncertain	0.12	D
DEOGEN2	Benign	0.22	T
LIST_S2	Benign	0.82	T
MutationAssessor	Pathogenic	4.6	H
MutationTaster	Benign	0.029	A
PROVEAN	Uncertain	-3.7	D
Sift4G	Pathogenic	0.0	D
GERP RS		4.5
Varity_R		0.75

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs267606898; hg19: chrM-13043; COSMIC: COSV62292993; COSMIC: COSV62292993;