22-30617412-G-T

Variant names:

• chr22-30617412-G-T
• rs76802001
• NM_000355.4:c.1023G>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_000355.4(TCN2):​c.1023G>T​(p.Pro341Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. P341P) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TCN2 NM_000355.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -1.94
• Publications: 9 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: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.89).
• BP7: Synonymous conserved (PhyloP=-1.94 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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCN2	NM_000355.4	MANE Select	c.1023G>T	p.Pro341Pro	synonymous	Exon 7 of 9	NP_000346.2
	TCN2	NM_001184726.2		c.942G>T	p.Pro314Pro	synonymous	Exon 7 of 9	NP_001171655.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TCN2	ENST00000215838.8	TSL:1 MANE Select	c.1023G>T	p.Pro341Pro	synonymous	Exon 7 of 9	ENSP00000215838.3
	TCN2	ENST00000407817.3	TSL:1	c.942G>T	p.Pro314Pro	synonymous	Exon 7 of 9	ENSP00000384914.3
	TCN2	ENST00000698271.1		c.1053G>T	p.Pro351Pro	synonymous	Exon 7 of 9	ENSP00000513642.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 24

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.89
CADD	Benign	0.063
DANN	Benign	0.55
PhyloP100		-1.9

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs76802001; hg19: chr22-31013399;