Genetic Variant TCN1:p.Ser406Arg (chr11-59853225-A-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001062.4(TCN1):c.1218T>A(p.Ser406Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000889 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

TCN1
NM_001062.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.0690

Variant links:

Genes affected

TCN1 (HGNC:11652): (transcobalamin 1) 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 protein is a major constituent of secondary granules in neutrophils and facilitates the transport of cobalamin into cells. [provided by RefSeq, Jul 2008]

TCN1 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCN1	NM_001062.4 link	c.1218T>A	p.Ser406Arg	missense_variant	Exon 8 of 9	ENST00000257264.4	NP_001053.2	P20061

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCN1	ENST00000257264.4 link	c.1218T>A	p.Ser406Arg	missense_variant	Exon 8 of 9	1	NM_001062.4	ENSP00000257264.3		P20061
TCN1	ENST00000529251.1 link	n.217T>A		non_coding_transcript_exon_variant	Exon 2 of 3	3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251320

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135826

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:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000889

AC:

AN:

1461874

Hom.:

Cov.:

AF XY:

0.00000825

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:

0.0000927

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Transcobalamin I deficiency

Uncertain:1

May 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine, which is neutral and polar, with arginine, which is basic and polar, at codon 406 of the TCN1 protein (p.Ser406Arg). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with TCN1-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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 v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.63

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.39

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.070

Eigen

Benign

-0.32

Eigen_PC

Benign

-0.50

FATHMM_MKL

Benign

0.11

LIST_S2

Benign

0.74

M_CAP

Benign

0.0088

MetaRNN

Uncertain

0.64

MetaSVM

Benign

-1.0

MutationAssessor

Uncertain

2.1

PrimateAI

Benign

0.39

PROVEAN

Uncertain

-2.9

REVEL

Benign

0.12

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Polyphen

1.0

Vest4

0.59

MutPred

0.41

Loss of glycosylation at S406 (P = 0.035);

MVP

0.53

MPC

0.10

ClinPred

0.98

GERP RS

-0.10

Varity_R

0.78

gMVP

0.70

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

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