VCV000690169.5 - ClinVar

NC_012920.1(MT-TS2):m.12241del

Germline

Reviewed by expert panel

Reviewed by expert panel. Learn more about how ClinVar calculates review status.

Uncertain Significance

for Mitochondrial disease

Classification is based on the expert panel submission

Aug 2023 by ClinGen Mitochondrial Disease Nuclear and Mitochondrial Va…

The classification is calculated by NCBI based on data from submitters. Read our rules for calculating the aggregate classification.

FDA Recognized Database

Somatic

No data submitted for somatic clinical impact

Somatic

No data submitted for oncogenicity

Variant Details

Identifiers

NC_012920.1(MT-TS2):m.12241del

Variation ID: 690169 Accession: VCV000690169.5

Type and length

Deletion, 1 bp

Location

MT: 12237 (GRCh38) [ NCBI UCSC ] MT: 12237 (GRCh37) [ NCBI UCSC ]

Timeline in ClinVar

	First in ClinVar Help The date this variant first appeared in ClinVar with each type of classification.	Last submission Help The date of the most recent submission for each type of classification for this variant.	Last evaluated Help The most recent date that a submitter evaluated this variant for each type of classification.
Germline	Sep 22, 2019	Mar 23, 2024	Aug 22, 2023

HGVS

Nucleotide	Protein	Molecular consequence
NC_012920.1:m.12241del

Protein change

Other names

Canonical SPDI

NC_012920.1:12236:CCCCC:CCCC

Global minor allele frequency (GMAF) Help The global minor allele frequency calculated by the 1000 Genomes Project. The minor allele at this location is indicated in parentheses and may be different from the allele represented by this VCV record.

Allele frequency Help The frequency of the allele represented by this VCV record.

Links

ClinGen: CA915952144 dbSNP: rs1603223633 VarSome

Genes

Gene	OMIM	ClinGen Gene Dosage Sensitivity Curation		Variation Viewer Help Links to Variation Viewer, a genome browser to view variation data from NCBI databases.	Related variants
Gene	OMIM	HI score Help The haploinsufficiency score for the gene, curated by ClinGen’s Dosage Sensitivity Curation task team.	TS score Help The triplosensitivity score for the gene, curated by ClinGen’s Dosage Sensitivity Curation task team.		Within gene Help The number of variants in ClinVar that are contained within this gene, with a link to view the list of variants.	All Help The number of variants in ClinVar for this gene, including smaller variants within the gene and larger CNVs that overlap or fully contain the gene.
MT-TS2		-	-	GRCh38	28	48

Conditions - Germline

Condition Help The condition for this variant-condition (RCV) record in ClinVar.	Classification Help The aggregate germline classification for this variant-condition (RCV) record in ClinVar. The number of submissions that contribute to this aggregate classification is shown in parentheses. (# of submissions)	Review status Help The aggregate review status for this variant-condition (RCV) record in ClinVar. This value is calculated by NCBI based on data from submitters. Read our rules for calculating the review status.	Last evaluated Help The most recent date that a submitter evaluated this variant for the condition.	Variation/condition record Help The RCV accession number, with most recent version number, for the variant-condition record, with a link to the RCV web page.
MELAS syndrome	Benign (1)	criteria provided, single submitter	Jul 12, 2019	RCV000851056.1
See cases	Uncertain significance (1)	criteria provided, single submitter	Nov 7, 2019	RCV001250990.2
Mitochondrial disease	Uncertain significance (1)	reviewed by expert panel	Aug 22, 2023	RCV003985435.2

Submissions - Germline

Classification Help The submitted germline classification for each SCV record. (Last evaluated)	Review status Help Stars represent the review status, or the level of review supporting the submitted (SCV) record. This value is calculated by NCBI based on data from the submitter. Read our rules for calculating the review status. This column also includes a link to the submitter’s assertion criteria if provided, and the collection method. (Assertion criteria)	Condition Help The condition for the classification, provided by the submitter for this submitted (SCV) record. This column also includes the affected status and allele origin of individuals observed with this variant.	Submitter Help The submitting organization for this submitted (SCV) record. This column also includes the SCV accession and version number, the date this SCV first appeared in ClinVar, and the date that this SCV was last updated in ClinVar.	Expand all rows Collapse all rows Help This column includes more information supporting the classification, including citations, the comment on classification, and detailed evidence provided as observations of the variant by the submitter.
Uncertain Significance (Aug 22, 2023) C Contributing to aggregate classification	reviewed by expert panel (McCormick et al. (Hum Mutat. 2020))	Mitochondrial disease (Mitochondrial inheritance)	ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel, ClinGen FDA Recognized Database Accession: SCV004801738.1 First in ClinVar: Mar 23, 2024 Last updated: Mar 23, 2024	Other databases https://erepo.clinicalgenome.org… https://erepo.clinicalgenome.org/evrepo/ui/interpretation/2a4ee240-e4a1-419d-bbfd-d0e83b796214 Comment: show The m.12241del variant in MT-TS2 was reviewed by the Mitochondrial Disease Variant Curation Expert Panel on August 22, 2023. This variant has not been reported in the medical literature as causative in affected individuals or families with primary mitochondrial disease to our knowledge. There are several occurrences in population databases. The frequency in the MITOMAP GenBank sequences is 16/61,168 (0.026%). The frequency in the Helix dataset is 81/195,983 (0.041%) homoplasmic occurrences in addition to 22 heteroplasmic occurrences. The frequency in gnomAD v3.1.2 is 53/56,425 (0.094%) and these occurrences are homoplasmic in individuals from various backgrounds. In all three population databases, this variant is seen across individuals from different haplogroups. MitoTIP suggests this variant is benign (37th percentile; BP4). 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 uncertain significance 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 22, 2023. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): BP4. (less) Observation: 1 Collection method: curation Allele origin: germline Affected status: unknown Observation 1 Collection method: curation Allele origin: germline Affected status: unknown

Benign (Jul 12, 2019) N Not contributing to aggregate classification	criteria provided, single submitter (Modified ACMG Guidelines (Unpublished))	MELAS syndrome	Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine Accession: SCV000993290.1 First in ClinVar: Sep 22, 2019 Last updated: Sep 22, 2019	Publications: PubMed (1) PubMed: 31965079 Comment: show The NC_012920.1:m.12241delC variant in MT-TS2 gene is interpreted to be a Benign variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes reported in the guidelines: BS1, BS2 (less) Observation: 1 Collection method: clinical testing Allele origin: germline Affected status: unknown Observation 1 Collection method: clinical testing Allele origin: germline Affected status: unknown

Uncertain significance (Nov 07, 2019) N Not contributing to aggregate classification	criteria provided, single submitter (ACMG Guidelines, 2015)	see cases	Centre for Mendelian Genomics, University Medical Centre Ljubljana Accession: SCV001368300.2 First in ClinVar: Aug 08, 2020 Last updated: Aug 08, 2020	Comment: show This variant was classified as: Uncertain significance. The available evidence on this variant's pathogenicity is insufficient or conflicting. The following ACMG criteria were applied in classifying this variant: No criteria apply. This variant was detected in homozygous state. (less) Observation: 1 Collection method: clinical testing Allele origin: unknown Affected status: yes more Observation 1 Collection method: clinical testing Allele origin: unknown Affected status: yes Clinical Features: Visual impairment (present) , Cataract (disease) (present) , Pigmentary retinopathy (present) , Macular dystrophy (present)

Comment:

The m.12241del variant in MT-TS2 was reviewed by the Mitochondrial Disease Variant Curation Expert Panel on August 22, 2023. This variant has not been reported in the medical literature as causative in affected individuals or families with primary mitochondrial disease to our knowledge. There are several occurrences in population databases. The frequency in the MITOMAP GenBank sequences is 16/61,168 (0.026%). The frequency in the Helix dataset is 81/195,983 (0.041%) homoplasmic occurrences in addition to 22 heteroplasmic occurrences. The frequency in gnomAD v3.1.2 is 53/56,425 (0.094%) and these occurrences are homoplasmic in individuals from various backgrounds. In all three population databases, this variant is seen across individuals from different haplogroups. MitoTIP suggests this variant is benign (37th percentile; BP4). 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 uncertain significance 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 22, 2023. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): BP4.

Comment:

This variant was classified as: Uncertain significance. The available evidence on this variant's pathogenicity is insufficient or conflicting. The following ACMG criteria were applied in classifying this variant: No criteria apply. This variant was detected in homozygous state.

Citations for germline classification of this variant

Title	Author	Journal	Year	Link
Interpretation of mitochondrial tRNA variants.	Wong LC	Genetics in medicine : official journal of the American College of Medical Genetics	2020	PMID: 31965079
https://erepo.clinicalgenome.org/evrepo/ui/interpretation/2a4ee240-e4a1-419d-bbfd-d0e83b796214	-	-	-	-

Text-mined citations for rs1603223633 ...

These citations are identified by LitVar using the rs number, so they may include citations for more than one variant at this location. Please review the LitVar results carefully for your variant of interest.

Record last updated Apr 13, 2026