22-30612938-A-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PP3_Moderate

The NM_000355.4(TCN2):c.323A>T(p.Tyr108Phe) variant causes a missense change. The variant allele was found at a frequency of 0.0000359 in 1,613,960 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y108C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000037 ( 0 hom. )

Consequence

TCN2
NM_000355.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 5.39

Publications

0 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: Uncertain_significance. The variant received 2 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.846

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000355.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCN2	NM_000355.4	MANE Select	c.323A>T	p.Tyr108Phe	missense	Exon 3 of 9	NP_000346.2
	TCN2	NM_001184726.2		c.323A>T	p.Tyr108Phe	missense	Exon 3 of 9	NP_001171655.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TCN2	ENST00000215838.8	TSL:1 MANE Select	c.323A>T	p.Tyr108Phe	missense	Exon 3 of 9	ENSP00000215838.3
TCN2	ENST00000407817.3	TSL:1	c.323A>T	p.Tyr108Phe	missense	Exon 3 of 9	ENSP00000384914.3
TCN2	ENST00000698271.1		c.323A>T	p.Tyr108Phe	missense	Exon 3 of 9	ENSP00000513642.1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152084

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000358

AC:

AN:

251372

AF XY:

0.0000368

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000704

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000369

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000330

AC XY:

AN XY:

727234

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.000521

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.0000378

AC:

AN:

1112004

Other (OTH)

AF:

0.000149

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.509

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152084

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74292

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41414

American (AMR)

AF:

0.0000655

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

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:

0.000113

Hom.:

Bravo

AF:

0.0000340

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000296

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Sep 27, 2021

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.323A>T (p.Y108F) alteration is located in exon 3 (coding exon 3) of the TCN2 gene. This alteration results from a A to T substitution at nucleotide position 323, causing the tyrosine (Y) at amino acid position 108 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Transcobalamin II deficiency

Uncertain:1

Oct 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 108 of the TCN2 protein (p.Tyr108Phe). This variant is present in population databases (rs781309237, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with TCN2-related conditions. ClinVar contains an entry for this variant (Variation ID: 566888). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TCN2 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Benign

-0.10

BayesDel_noAF

Benign

-0.21

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.22

Eigen

Pathogenic

0.71

Eigen_PC

Pathogenic

0.66

FATHMM_MKL

Uncertain

0.82

LIST_S2

Uncertain

0.86

M_CAP

Benign

0.041

MetaRNN

Pathogenic

0.85

MetaSVM

Benign

-0.50

MutationAssessor

Pathogenic

3.1

PhyloP100

5.4

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-2.2

REVEL

Uncertain

0.34

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.66

MutPred

0.78

Loss of methylation at R113 (P = 0.1693)

MVP

0.56

MPC

0.059

ClinPred

0.69

GERP RS

5.4

Varity_R

0.75

gMVP

0.41

Mutation Taster

=27/73

disease causing

(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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over