19-8302475-G-A

Variant names:

• chr19-8302475-G-A
• rs2227289
• NM_016579.4:c.837C>T

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP7

The NM_016579.4(CD320):​c.837C>T​(p.Thr279Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,614,066 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T279T) has been classified as Benign.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CD320 NM_016579.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.137
• Publications: 15 publications found

Genes affected

CD320 (HGNC:16692): (CD320 molecule) This gene encodes the transcobalamin receptor that is expressed at the cell surface. It mediates the cellular uptake of transcobalamin bound cobalamin (vitamin B12), and is involved in B-cell proliferation and immunoglobulin secretion. Mutations in this gene are associated with methylmalonic aciduria. Alternatively spliced transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Jan 2011]

CD320 Gene-Disease associations (from GenCC):

• methylmalonic acidemia due to transcobalamin receptor defect

  Inheritance: Unknown, AR Classification: DEFINITIVE, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, ClinGen, Laboratory for Molecular Medicine

ACMG classification

Our verdict: Likely_benign. The variant received -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (REVEL=0.031).
• BP7: Synonymous conserved (PhyloP=0.137 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_016579.4. 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
	CD320	NM_016579.4	MANE Select	c.837C>T	p.Thr279Thr	synonymous	Exon 5 of 5	NP_057663.1
	CD320	NM_001165895.2		c.711C>T	p.Thr237Thr	synonymous	Exon 4 of 4	NP_001159367.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CD320	ENST00000301458.10	TSL:1 MANE Select	c.837C>T	p.Thr279Thr	synonymous	Exon 5 of 5	ENSP00000301458.4
	CD320	ENST00000596002.5	TSL:1	n.*1125C>T		non_coding_transcript_exon	Exon 5 of 5	ENSP00000471773.1
	CD320	ENST00000596002.5	TSL:1	n.*1125C>T		3_prime_UTR	Exon 5 of 5	ENSP00000471773.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152116 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251384 AF XY: 0.00

Gnomad AFR exome AF: 0.0000616

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461832 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727214

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53372

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112000

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152234 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74446

African (AFR) AF: 0.0000241 AC: 1 AN: 41494

American (AMR) AF: 0.0000654 AC: 1 AN: 15294

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.000193 AC: 1 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10622

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.00 Hom.: 65

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.85
CADD	Benign	0.79
DANN	Benign	0.51
PhyloP100		0.14
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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

Other links and lift over

dbSNP: rs2227289; hg19: chr19-8367359;