rs199474666

chrM-3274-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3 PP5

The ENST00000386347.1(MT-TL1):n.45A>G variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Mitomap GenBank: Absent
• Consequence: MT-TL1 ENST00000386347.1 non_coding_transcript_exon
• Scores: Mitotip Pathogenic 16
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1 Neuropsychiatric-syndrome-+-cataract
• Conservation: PhyloP100: 0.987

Genes affected

MT-TL1 (HGNC:7490): (mitochondrially encoded tRNA leucine 1 (UUA/G)) Implicated in cardiomyopathy. [provided by Alliance of Genome Resources, Apr 2022]

TRNL1 (HGNC:):

MT-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]

MT-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 4 ACMG points.

• PM2: No frequency data in Mitomap. Probably very rare.
• PP3: Mitotip and hmtvar scores support pathogenic criterium.
• PP5: Variant M-3274-A-G is Pathogenic according to our data. Variant chrM-3274-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 9598.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TRNL1	TRNL1.1	n.45A>G		non_coding_transcript_exon_variant	1/1
RNR2	RNR2.1			downstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MT-TL1	ENST00000386347.1	n.45A>G		non_coding_transcript_exon_variant	1/1
MT-ND1	ENST00000361390.2			upstream_gene_variant				P1
MT-RNR2	ENST00000387347.2			downstream_gene_variant

Frequencies

GnomAD4 exome Cov.: 0

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

Mitomap

Neuropsychiatric-syndrome-+-cataract

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neuropsychiatric disorder and early-onset cataract Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 27, 2001

- -

Juvenile myopathy, encephalopathy, lactic acidosis AND stroke Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Jul 12, 2019

The NC_012920.1:m.3274A>G variant in MT-TL1 gene is interpreted to be a Pathogenic variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes reported in the guidelines: PS3, PM7, PM8, PM9 -

MERRF syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

MGZ Medical Genetics Center

Aug 23, 2022

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Mitotip	Pathogenic	16
Hmtvar	Pathogenic	0.55

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs199474666; hg19: chrM-3275;