M-3252-A-T

Variant names:

• chrM-3252-A-T
• rs199474661
• unassigned_transcript_4788:c.23A>T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Mitomap GenBank: Absent
• Consequence: TRNL1 missense
• Scores: Mitotip Uncertain 11
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1 MELAS,EXIT
• Conservation: PhyloP100: 6.99

Genes affected

TRNL1 (HGNC:7490): (mitochondrially encoded tRNA leucine 1 (UUA/G)) Implicated in cardiomyopathy. [provided by Alliance of Genome Resources, Apr 2022]

ND1 (HGNC:7455): (mitochondrially encoded NADH dehydrogenase 1) Enables NADH dehydrogenase (ubiquinone) activity. Involved in mitochondrial electron transport, NADH to ubiquinone and mitochondrial respiratory chain complex I assembly. Located in mitochondrial membrane. Part of mitochondrial respiratory chain complex I. Implicated in several diseases, including MELAS syndrome; neurodegenerative disease (multiple); optic nerve disease (multiple); toxic shock syndrome; and type 2 diabetes mellitus. Biomarker of Alzheimer's disease; Parkinson's disease; and multiple sclerosis. [provided by Alliance of Genome Resources, Apr 2022]

RNR2 (HGNC:7471): (mitochondrially encoded 16S RNA) Enables G protein-coupled receptor binding activity; protein self-association; and receptor antagonist activity. Involved in several processes, including leukocyte chemotaxis; negative regulation of cell death; and negative regulation of neuroinflammatory response. Located in several cellular components, including mitochondrion; perinuclear region of cytoplasm; and sperm midpiece. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: No frequency data in Mitomap. Probably very rare.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TRNL1	unassigned_transcript_4788	c.23A>T	p.Asn8Ile	missense_variant	Exon 1 of 1
ND1	unassigned_transcript_4789	c.-55A>T		upstream_gene_variant
RNR2	unassigned_transcript_4787	n.*23A>T		downstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt

Frequencies

GnomAD4 exome Cov.: 0

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

Mitomap

MELAS,EXIT

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

MELAS syndrome Uncertain:1

Jul 12, 2019

Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The NC_012920.1:m.3252A>T variant in MT-TL1 gene is interpreted to be a Unknown Significance variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes reported in the guidelines: PM2, PM9, PP6 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Mitotip	Uncertain	11
Hmtvar	Benign	0.15

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs199474661; hg19: chrM-3253;