NM_004048.4:c.1A>C

Variant names:

• chr15-44711547-A-C
• NM_004048.4:c.1A>C

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_004048.4(B2M):​c.1A>C​(p.Met1?) variant causes a initiator codon 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 other (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: B2M NM_004048.4 initiator_codon
• Clinical Significance: - - O:1
• Conservation: PhyloP100: 2.09

Genes affected

B2M (HGNC:914): (beta-2-microglobulin) This gene encodes a serum protein found in association with the major histocompatibility complex (MHC) class I heavy chain on the surface of nearly all nucleated cells. The protein has a predominantly beta-pleated sheet structure that can form amyloid fibrils in some pathological conditions. The encoded antimicrobial protein displays antibacterial activity in amniotic fluid. A mutation in this gene has been shown to result in hypercatabolic hypoproteinemia.[provided by RefSeq, Aug 2014]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Start lost variant, next in-frame start position is after 2 pathogenic variants. Next in-frame start position is after 354 CDS bases. Genomic position: 44716336. Lost 0.983 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
B2M	NM_004048.4	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 4	ENST00000648006.3	NP_004039.1
B2M	XM_005254549.4	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 2		XP_005254606.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
B2M	ENST00000648006.3	c.1A>C	p.Met1?	initiator_codon_variant	Exon 1 of 4		NM_004048.4	ENSP00000497910.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: -

Submissions summary: Other:1

Revision: -

Submissions by phenotype

Neoplasm Other:1

-, criteria provided, single submitter

clinical testing

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Mar 04, 2025

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	21
DANN	Benign	0.90
DEOGEN2	Benign	0.024	T;T;T;T
Eigen	Benign	0.045
Eigen_PC	Benign	0.027
FATHMM_MKL	Uncertain	0.92	D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.97	D;D;D;D
MetaSVM	Benign	-0.68	T
PROVEAN	Benign	-1.4	N;N;N;.
REVEL	Benign	0.27
Sift	Pathogenic	0.0	D;D;D;.
Sift4G	Pathogenic	0.0	D;D;D;.
Polyphen		0.83	P;P;P;P
Vest4		0.83
MutPred		0.86		Loss of catalytic residue at M1 (P = 0.0348);Loss of catalytic residue at M1 (P = 0.0348);Loss of catalytic residue at M1 (P = 0.0348);Loss of catalytic residue at M1 (P = 0.0348);
MVP		0.94
ClinPred		0.84	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.47

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: chr15-45003745; COSMIC: COSV62563658; COSMIC: COSV62563658;