Genetic Variant NM_021830.5:c.1102G>T (chr10-100989312-G-T) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1PM2BP4

The NM_021830.5(TWNK):c.1102G>T(p.Val368Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,614,104 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V368I) has been classified as Benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TWNK
NM_021830.5 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 2.57

Variant links:

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 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM1

In a region_of_interest Required for hexamers formation and DNA helicase activity (size 251) in uniprot entity PEO1_HUMAN there are 18 pathogenic changes around while only 2 benign (90%) in NM_021830.5

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.3524533).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TWNK	NM_021830.5 link	c.1102G>T	p.Val368Leu	missense_variant	Exon 1 of 5	ENST00000311916.8	NP_068602.2	Q96RR1-1E5KSY5Q9H6V3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TWNK	ENST00000311916.8 link	c.1102G>T	p.Val368Leu	missense_variant	Exon 1 of 5	1	NM_021830.5	ENSP00000309595.2		Q96RR1-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152138

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251324

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135872

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461848

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727222

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152256

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74470

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000653

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

ExAC

AF:

0.00000824

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.23

BayesDel_addAF

Uncertain

0.10

BayesDel_noAF

Uncertain

-0.010

CADD

Uncertain

DANN

Uncertain

0.99

DEOGEN2

Benign

0.12

T;.

Eigen

Benign

0.13

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.91

D;D

M_CAP

Uncertain

0.19

MetaRNN

Benign

0.35

T;T

MetaSVM

Uncertain

0.034

MutationAssessor

Benign

1.6

L;L

PROVEAN

Benign

-1.4

N;N

REVEL

Uncertain

0.50

Sift

Benign

0.16

T;T

Sift4G

Benign

0.23

T;T

Polyphen

0.59

P;P

Vest4

0.42

MutPred

0.53

Loss of MoRF binding (P = 0.1011);Loss of MoRF binding (P = 0.1011);

MVP

0.87

MPC

0.55

ClinPred

0.54

GERP RS

5.1

Varity_R

0.11

gMVP

0.77

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.070

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

LitVar

Other links and lift over