19-8302551-C-A

Variant names:

• chr19-8302551-C-A
• rs369347295
• NM_016579.4:c.761G>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_016579.4(CD320):​c.761G>T​(p.Arg254Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,613,844 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R254Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (1 hom.)
• Consequence: CD320 NM_016579.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.253
• Publications: 1 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: AR, Unknown Classification: DEFINITIVE, SUPPORTIVE, LIMITED Submitted by: ClinGen, Orphanet, Ambry Genetics, Laboratory for Molecular Medicine, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CD320	NM_016579.4	MANE Select	c.761G>T	p.Arg254Leu	missense	Exon 5 of 5	NP_057663.1	Q9NPF0-1
	CD320	NM_001165895.2		c.635G>T	p.Arg212Leu	missense	Exon 4 of 4	NP_001159367.1	Q9NPF0-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CD320	ENST00000301458.10	TSL:1 MANE Select	c.761G>T	p.Arg254Leu	missense	Exon 5 of 5	ENSP00000301458.4	Q9NPF0-1
	CD320	ENST00000596002.5	TSL:1	n.*1049G>T		non_coding_transcript_exon	Exon 5 of 5	ENSP00000471773.1	M0R1C4
	CD320	ENST00000596002.5	TSL:1	n.*1049G>T		3_prime_UTR	Exon 5 of 5	ENSP00000471773.1	M0R1C4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152096 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

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

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461748 Hom.: 1 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727150

African (AFR) AF: 0.0000299 AC: 1 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: 39700

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53316

Middle Eastern (MID) AF: 0.000347 AC: 2 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152096 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74298

African (AFR) AF: 0.0000242 AC: 1 AN: 41404

American (AMR) AF: 0.00 AC: 0 AN: 15268

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68016

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.00 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Uncertain	0.025	T
BayesDel_noAF	Benign	-0.20
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.078	T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.029	N
LIST_S2	Benign	0.66	T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.093	T
MetaSVM	Uncertain	-0.083	T
MutationAssessor	Benign	1.4	L
PhyloP100		0.25
PrimateAI	Benign	0.26	T
PROVEAN	Benign	-1.9	N
REVEL	Benign	0.16
Sift	Benign	0.67	T
Sift4G	Benign	0.24	T
Polyphen		0.016	B
Vest4		0.20
MutPred		0.48		Loss of MoRF binding (P = 0.0063)
MVP		0.84
MPC		0.39
ClinPred		0.78	D
GERP RS		1.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.053
gMVP		0.42
Mutation Taster		=98/2	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.71		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.71		Position offset: -3

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

Other links and lift over

dbSNP: rs369347295; hg19: chr19-8367435;