NM_000355.4:c.18C>T

Variant names:

• chr22-30607349-C-T
• rs773549344
• NM_000355.4:c.18C>T

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_Strong BP6_Moderate BP7

The NM_000355.4(TCN2):​c.18C>T​(p.Ala6Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000178 in 1,461,884 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000018 (0 hom.)
• Consequence: TCN2 NM_000355.4 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.00100
• Publications: 0 publications found

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: PanelApp Australia, ClinGen, Ambry Genetics, Orphanet, G2P, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Benign. The variant received -7 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.53).
• BP6: Variant 22-30607349-C-T is Benign according to our data. Variant chr22-30607349-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 2979422.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=0.001 with no splicing effect.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCN2	NM_000355.4	MANE Select	c.18C>T	p.Ala6Ala	synonymous	Exon 1 of 9	NP_000346.2
	TCN2	NM_001184726.2		c.18C>T	p.Ala6Ala	synonymous	Exon 1 of 9	NP_001171655.1	P20062-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCN2	ENST00000215838.8	TSL:1 MANE Select	c.18C>T	p.Ala6Ala	synonymous	Exon 1 of 9	ENSP00000215838.3	P20062-1
	TCN2	ENST00000407817.3	TSL:1	c.18C>T	p.Ala6Ala	synonymous	Exon 1 of 9	ENSP00000384914.3	P20062-2
	TCN2	ENST00000947107.1		c.18C>T	p.Ala6Ala	synonymous	Exon 1 of 10	ENSP00000617166.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000318 AC: 8 AN: 251448 AF XY: 0.0000368

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000178 AC: 26 AN: 1461884 Hom.: 0 Cov.: 31 AF XY: 0.0000248 AC XY: 18 AN XY: 727244

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.000255 AC: 22 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112006

Other (OTH) AF: 0.0000497 AC: 3 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000312 Hom.: 0

Bravo AF: 0.00000756

ClinVar

ClinVar submissions

Significance: Likely benign

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	-	1	Transcobalamin II deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.53
CADD	Benign	11
DANN	Benign	0.89
PhyloP100		0.0010
PromoterAI		-0.21	Neutral

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs773549344; hg19: chr22-31003336;