2-21034830-C-A

Position:

• chr2-21034830-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000384.3(APOB):​c.890G>T​(p.Arg297Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000208 in 1,439,440 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R297C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: APOB NM_000384.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.48

Genes affected

APOB (HGNC:603): (apolipoprotein B) This gene product is the main apolipoprotein of chylomicrons and low density lipoproteins (LDL), and is the ligand for the LDL receptor. It occurs in plasma as two main isoforms, apoB-48 and apoB-100: the former is synthesized exclusively in the gut and the latter in the liver. The intestinal and the hepatic forms of apoB are encoded by a single gene from a single, very long mRNA. The two isoforms share a common N-terminal sequence. The shorter apoB-48 protein is produced after RNA editing of the apoB-100 transcript at residue 2180 (CAA->UAA), resulting in the creation of a stop codon, and early translation termination. Mutations in this gene or its regulatory region cause hypobetalipoproteinemia, normotriglyceridemic hypobetalipoproteinemia, and hypercholesterolemia due to ligand-defective apoB, diseases affecting plasma cholesterol and apoB levels. [provided by RefSeq, Dec 2019]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
APOB	NM_000384.3	c.890G>T	p.Arg297Leu	missense_variant	8/29	ENST00000233242.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
APOB	ENST00000233242.5	c.890G>T	p.Arg297Leu	missense_variant	8/29	1	NM_000384.3	P1
APOB	ENST00000399256.4	c.890G>T	p.Arg297Leu	missense_variant	8/17	1
APOB	ENST00000673739.2	c.*196G>T		3_prime_UTR_variant, NMD_transcript_variant	7/25
APOB	ENST00000673882.2	c.*196G>T		3_prime_UTR_variant, NMD_transcript_variant	7/23

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251490 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135920

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.000139

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000208 AC: 3 AN: 1439440 Hom.: 0 Cov.: 27 AF XY: 0.00000139 AC XY: 1 AN XY: 717578

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000562

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.51
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.16	.;T
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.89	.;D
M_CAP	Uncertain	0.10	D
MetaRNN	Uncertain	0.56	D;D
MetaSVM	Benign	-0.55	T
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.33	T
PROVEAN	Pathogenic	-4.6	D;D
REVEL	Uncertain	0.37
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Vest4		0.43
MutPred		0.66		Loss of MoRF binding (P = 0.021);Loss of MoRF binding (P = 0.021);
MVP		0.70
MPC		0.25
ClinPred		0.99	D
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
gMVP		0.56

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

LitVar

Other links and lift over

dbSNP: rs147223101; hg19: chr2-21257702; COSMIC: COSV51926923;