rs199474821

chrM-7511-T-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PP3 PP5_Very_Strong

The ENST00000387416.2(MT-TS1):n.4A>G variant causes a non coding transcript exon change. Variant has been reported in ClinVar as Likely pathogenic (★★★).

• Frequency: Mitomap GenBank: Absent
• Consequence: MT-TS1 ENST00000387416.2 non_coding_transcript_exon
• Scores: Mitotip Pathogenic 17
• Clinical Significance: Likely pathogenic reviewed by expert panel P:4 O:1 SNHL/Deafness
• Conservation: PhyloP100: 4.90

Genes affected

MT-TS1 (HGNC:7497): (mitochondrially encoded tRNA serine 1 (UCN))

TRNS1 (HGNC:):

MT-TD (HGNC:7478): (mitochondrially encoded tRNA aspartic acid)

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM2: No frequency data in Mitomap. Probably very rare.
• PP3: Mitotip and hmtvar scores support pathogenic criterium.
• PP5: Variant M-7511-T-C is Pathogenic according to our data. Variant chrM-7511-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 9566.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TRNS1	TRNS1.1	n.4A>G		non_coding_transcript_exon_variant	1/1
TRND	TRND.1			upstream_gene_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MT-TS1	ENST00000387416.2	n.4A>G		non_coding_transcript_exon_variant	1/1
MT-TD	ENST00000387419.1			upstream_gene_variant

Frequencies

GnomAD4 exome Cov.: 0

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

Gnomad homoplasmic AF: 0.000035 AC: 2 AN: 56429

Gnomad heteroplasmic AF: 0.0 AC: 0 AN: 56429

Mitomap

SNHL/Deafness

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Mitochondrial non-syndromic sensorineural hearing loss Pathogenic:1 Other:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Dec 01, 2002	- -
not provided, no classification provided	literature only	GeneReviews	-	- -

Mitochondrial complex IV deficiency, nuclear type 1 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Mendelics

May 04, 2022

- -

Mitochondrial disease Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

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

Nov 30, 2022

The m.7511T>C variant in MT-TS1 has been reported in ten unrelated probands from ten kindreds of varying ethnic background with nonsyndromic sensorineural hearing loss (PS4_moderate; PMIDs: 10371545, 12461693, 15670746, 18340555, 26279247, 25968158, 28320335, 29257206). In these families, the variant is present in family members with and without hearing loss. Hearing loss was variable overall when present, ranging from mild to profound. Age of onset of hearing loss varied from childhood to adulthood. Hearing loss was stable in some individuals and progressive in others. Some individuals also reported tinnitus and vertigo. There has been no other organ system involvement reported to date (although it is not clear if other organ systems were assessed in affected individuals). Muscle biopsy was not routinely performed in affected individuals however one individual did have COX-deficient fibers and complex IV deficiency (PMID: 10371545). The variant was generally present at homoplasmy (in maternal family members with and without hearing loss), however there were some heteroplasmic occurrences (PMIDs: 10371545, 12461693, 15670746, 26279247, 29257206). Penetrance differed across reported families, and several modifying factors were discussed, including variants in the genes PCDH15 (PMID: 26279247) and YARS2 (PMID: 25968158). Affected and unaffected individuals in these families had the variant and there was no correlation between severity and heteroplasmy level, thus preventing consideration for PP1. There are no de novo occurrences of this variant reported to our knowledge. The computational predictor MitoTIP suggests this variant is pathogenic (78.1 percentile) and HmtVAR predicts it to be pathogenic score of 0.75 (PP3). This variant is present in the healthy population, which is to be expected given the known reduced penetrance of this variant. Single fiber testing (PMID: 10371545) and cybrid analysis (PMID: 14960712) support the pathogenicity of this variant (PS3_moderate), as do other functional assays performed (PMIDs: 31685661, 16361254). This variant meets criteria to be classified as of uncertain significance however this Expert Panel elected to modify the classification to likely pathogenic given the overwhelming evidence of pathogenicity. Furthermore, the mitochondrial DNA variant specifications are known to not be optimized for variants that tend to be homoplasmic in nature and/or have reduced penetrance, such as the common mitochondrial variants associated with nonsyndromic hearing loss. This classification was approved by the NICHD/NINDS U24 ClinGen Mitochondrial Disease Variant Curation Expert Panel on November 30, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): PS4_moderate, PS3_moderate, PP3. -

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.7511T>C variant in MT-TS1 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, PS5, PM7 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Mitotip	Pathogenic	17
Hmtvar	Pathogenic	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: rs199474821; hg19: chrM-7512;