ENST00000370228.2:c.*1C>T

Variant names:

• chr10-100991026-C-T
• rs3740487
• ENST00000370228.2:c.*1C>T

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_Strong BP6_Moderate

The ENST00000370228.2(TWNK):​c.*1C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000111 in 1,613,778 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.000092 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (1 hom.)
• Consequence: TWNK ENST00000370228.2 3_prime_UTR
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.952
• Publications: 29 publications found

Genes affected

TWNK (HGNC:1160): (twinkle mtDNA helicase) This gene encodes a hexameric DNA helicase which unwinds short stretches of double-stranded DNA in the 5' to 3' direction and, along with mitochondrial single-stranded DNA binding protein and mtDNA polymerase gamma, is thought to play a key role in mtDNA replication. The protein localizes to the mitochondrial matrix and mitochondrial nucleoids. Mutations in this gene cause infantile onset spinocerebellar ataxia (IOSCA) and progressive external ophthalmoplegia (PEO) and are also associated with several mitochondrial depletion syndromes. Alternative splicing results in multiple transcript variants encoding distinct isoforms.[provided by RefSeq, Aug 2009]

TWNK Gene-Disease associations (from GenCC):

• progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• mitochondrial DNA depletion syndrome 7 (hepatocerebral type)

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)
• autosomal dominant progressive external ophthalmoplegia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• mitochondrial DNA depletion syndrome, hepatocerebrorenal form

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Perrault syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).
• BP6: Variant 10-100991026-C-T is Benign according to our data. Variant chr10-100991026-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 1534801.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TWNK	NM_021830.5	c.1734+16C>T		intron_variant	Intron 4 of 4	ENST00000311916.8	NP_068602.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TWNK	ENST00000311916.8	c.1734+16C>T		intron_variant	Intron 4 of 4	1	NM_021830.5	ENSP00000309595.2

Frequencies

GnomAD3 genomes AF: 0.0000921 AC: 14 AN: 152046 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000132

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000955 AC: 24 AN: 251318 AF XY: 0.0000663

Gnomad AFR exome AF: 0.0000616

Gnomad AMR exome AF: 0.000260

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000114

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000113 AC: 165 AN: 1461732 Hom.: 1 Cov.: 33 AF XY: 0.000107 AC XY: 78 AN XY: 727154

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.000335 AC: 15 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5734

European-Non Finnish (NFE) AF: 0.000133 AC: 148 AN: 1111916

Other (OTH) AF: 0.0000166 AC: 1 AN: 60390

GnomAD4 genome AF: 0.0000921 AC: 14 AN: 152046 Hom.: 0 Cov.: 32 AF XY: 0.000108 AC XY: 8 AN XY: 74262

African (AFR) AF: 0.0000483 AC: 2 AN: 41374

American (AMR) AF: 0.000196 AC: 3 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5174

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10586

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.000132 AC: 9 AN: 68018

Other (OTH) AF: 0.00 AC: 0 AN: 2084

Alfa AF: 0.0000172 Hom.: 2813

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Benign:1

Jan 25, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	11
DANN	Benign	0.93
PhyloP100		0.95

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs3740487; hg19: chr10-102750783;