NM_000355.4:c.32T>C

Variant names:

• chr22-30607363-T-C
• NM_000355.4:c.32T>C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_000355.4(TCN2):​c.32T>C​(p.Leu11Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: TCN2 NM_000355.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.63

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]

ACMG classification

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, 0.834

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TCN2	NM_000355.4	c.32T>C	p.Leu11Pro	missense_variant	Exon 1 of 9	ENST00000215838.8	NP_000346.2
TCN2	NM_001184726.2	c.32T>C	p.Leu11Pro	missense_variant	Exon 1 of 9		NP_001171655.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TCN2	ENST00000215838.8	c.32T>C	p.Leu11Pro	missense_variant	Exon 1 of 9	1	NM_000355.4	ENSP00000215838.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Transcobalamin II deficiency Uncertain:1

Aug 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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. ClinVar contains an entry for this variant (Variation ID: 2104305). This variant has not been reported in the literature in individuals affected with TCN2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 11 of the TCN2 protein (p.Leu11Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Uncertain	0.14	D
BayesDel_noAF	Uncertain	-0.030
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.17	T;T;.
Eigen	Uncertain	0.22
Eigen_PC	Benign	0.11
FATHMM_MKL	Benign	0.26	N
LIST_S2	Benign	0.46	T;T;T
M_CAP	Benign	0.018	T
MetaRNN	Pathogenic	0.83	D;D;D
MetaSVM	Benign	-0.67	T
MutationAssessor	Pathogenic	3.0	M;.;M
PrimateAI	Benign	0.48	T
PROVEAN	Uncertain	-3.4	D;D;D
REVEL	Benign	0.28
Sift	Uncertain	0.022	D;D;D
Sift4G	Uncertain	0.040	D;D;D
Polyphen		0.99	D;D;.
Vest4		0.75
MutPred		0.67		Loss of helix (P = 0.0041);Loss of helix (P = 0.0041);Loss of helix (P = 0.0041);
MVP		0.71
MPC		0.054
ClinPred		1.0	D
GERP RS		3.5
Varity_R		0.52
gMVP		0.50

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr22-31003350;