NM_000355.4:c.523G>A

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS1

The NM_000355.4(TCN2):c.523G>A(p.Val175Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000235 in 1,614,178 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. V175V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00013 ( 1 hom. )

Consequence

TCN2
NM_000355.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:3

Conservation

PhyloP100: 2.67

Publications

2 publications found

Variant links:

Genes affected

TCN2 (HGNC:11653): (transcobalamin 2) This gene encodes a member of the vitamin B12-binding protein family. This family of proteins, alternatively referred to as R binders, is expressed in various tissues and secretions. This plasma protein binds cobalamin and mediates the transport of cobalamin into cells. This protein and other mammalian cobalamin-binding proteins, such as transcobalamin I and gastric intrisic factor, may have evolved by duplication of a common ancestral gene. Alternative splicing results in multiple transcript variants.[provided by RefSeq, May 2010]

TCN2 Gene-Disease associations (from GenCC):

transcobalamin II deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet

TCN2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.01498583).

BP6

Variant 22-30614444-G-A is Benign according to our data. Variant chr22-30614444-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 529784.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00124 (189/152300) while in subpopulation AFR AF = 0.00445 (185/41562). AF 95% confidence interval is 0.00393. There are 0 homozygotes in GnomAd4. There are 88 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCN2	NM_000355.4 link	c.523G>A	p.Val175Met	missense_variant	Exon 4 of 9	ENST00000215838.8	NP_000346.2	P20062-1
TCN2	NM_001184726.2 link	c.442G>A	p.Val148Met	missense_variant	Exon 4 of 9		NP_001171655.1	P20062-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCN2	ENST00000215838.8 link	c.523G>A	p.Val175Met	missense_variant	Exon 4 of 9	1	NM_000355.4	ENSP00000215838.3		P20062-1

Frequencies

GnomAD3 genomes

AF:

0.00124

AC:

189

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00446

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.000350

AC:

AN:

251398

AF XY:

0.000221

show subpopulations

Gnomad AFR exome

AF:

0.00449

Gnomad AMR exome

AF:

0.000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.000131

AC:

191

AN:

1461878

Hom.:

Cov.:

AF XY:

0.000113

AC XY:

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00388

AC:

130

AN:

33480

American (AMR)

AF:

0.000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000756

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000315

AC:

AN:

1112010

Other (OTH)

AF:

0.000182

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.462

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00124

AC:

189

AN:

152300

Hom.:

Cov.:

AF XY:

0.00118

AC XY:

AN XY:

74476

show subpopulations

African (AFR)

AF:

0.00445

AC:

185

AN:

41562

American (AMR)

AF:

0.0000654

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000386

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.000473

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.499

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000407

Hom.:

Bravo

AF:

0.00136

ESP6500AA

AF:

0.00363

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000404

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Transcobalamin II deficiency

Uncertain:1Benign:2

Nov 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Jan 03, 2023

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Uncertain:1

Apr 28, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.523G>A (p.V175M) alteration is located in exon 4 (coding exon 4) of the TCN2 gene. This alteration results from a G to A substitution at nucleotide position 523, causing the valine (V) at amino acid position 175 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

TCN2-related disorder

Benign:1

Jan 05, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.28

BayesDel_addAF

Benign

-0.35

BayesDel_noAF

Benign

-0.28

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.22

T;T;T;.

Eigen

Benign

0.055

Eigen_PC

Benign

-0.062

FATHMM_MKL

Benign

0.75

LIST_S2

Benign

0.83

T;T;T;T

M_CAP

Benign

0.045

MetaRNN

Benign

0.015

T;T;T;T

MetaSVM

Benign

-0.80

MutationAssessor

Pathogenic

3.0

M;.;.;.

PhyloP100

2.7

PrimateAI

Benign

0.47

PROVEAN

Benign

-1.5

N;.;N;N

REVEL

Uncertain

0.31

Sift

Uncertain

0.0010

D;.;D;D

Sift4G

Uncertain

0.0050

D;D;D;D

Polyphen

1.0

D;.;D;.

Vest4

0.58

MVP

0.52

MPC

0.057

ClinPred

0.13

GERP RS

3.3

Varity_R

0.36

gMVP

0.60

Mutation Taster

=75/25

polymorphism

(source)

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over