Variant 22-30623057-G-C details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3

The NM_000355.4(TCN2):c.1196G>C(p.Arg399Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000267 in 1,461,876 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. R399Q) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 30)

Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

TCN2
NM_000355.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: -0.457

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 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.752

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCN2	NM_000355.4 link	c.1196G>C	p.Arg399Pro	missense_variant	Exon 8 of 9	ENST00000215838.8	NP_000346.2	P20062-1
TCN2	NM_001184726.2 link	c.1115G>C	p.Arg372Pro	missense_variant	Exon 8 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.1196G>C	p.Arg399Pro	missense_variant	Exon 8 of 9	1	NM_000355.4	ENSP00000215838.3		P20062-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251458

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135902

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

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:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000267

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000275

AC XY:

AN XY:

727240

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:

0.0000351

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000259

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Transcobalamin II deficiency

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 26, 2020

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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with TCN2-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with proline at codon 399 of the TCN2 protein (p.Arg399Pro). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and proline. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.59

BayesDel_addAF

Benign

0.0025

BayesDel_noAF

Benign

-0.23

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.13

T;T;T;.

Eigen

Benign

-0.25

Eigen_PC

Benign

-0.39

FATHMM_MKL

Benign

0.17

LIST_S2

Benign

0.74

T;T;T;T

M_CAP

Benign

0.041

MetaRNN

Pathogenic

0.75

D;D;D;D

MetaSVM

Benign

-0.80

MutationAssessor

Uncertain

2.8

M;.;.;.

PrimateAI

Benign

0.23

PROVEAN

Benign

-2.2

N;.;N;N

REVEL

Benign

0.26

Sift

Uncertain

0.018

D;.;D;D

Sift4G

Uncertain

0.013

D;D;D;D

Polyphen

0.99

D;.;D;.

Vest4

0.50

MutPred

0.41

Gain of glycosylation at R399 (P = 0.0331);.;.;.;

MVP

0.54

MPC

0.039

ClinPred

0.89

GERP RS

2.1

Varity_R

0.98

gMVP

0.89

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

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over