2-21033498-C-A

Position:

chr2-21033498-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_000384.3(APOB):c.925G>T(p.Ala309Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,826 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A309T) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

APOB
NM_000384.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 0.708

Variant links:

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]

APOB links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.24347565).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APOB	NM_000384.3 linkuse as main transcript	c.925G>T	p.Ala309Ser	missense_variant	9/29	ENST00000233242.5	NP_000375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris
APOB	ENST00000233242.5 linkuse as main transcript	c.925G>T	p.Ala309Ser	missense_variant	9/29	1	NM_000384.3	ENSP00000233242	P1
APOB	ENST00000399256.4 linkuse as main transcript	c.925G>T	p.Ala309Ser	missense_variant	9/17	1		ENSP00000382200
APOB	ENST00000673739.2 linkuse as main transcript	c.*231G>T		3_prime_UTR_variant, NMD_transcript_variant	8/25			ENSP00000501110
APOB	ENST00000673882.2 linkuse as main transcript	c.*231G>T		3_prime_UTR_variant, NMD_transcript_variant	8/23			ENSP00000501253

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251452

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135902

show subpopulations

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:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461826

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727220

show subpopulations

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:

0.00

Gnomad4 NFE exome

AF:

0.00000809

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hypercholesterolemia, autosomal dominant, type B;C4551990:Familial hypobetalipoproteinemia 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 30, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt APOB protein function. ClinVar contains an entry for this variant (Variation ID: 895910). This variant has not been reported in the literature in individuals affected with APOB-related conditions. This variant is present in population databases (rs141888564, gnomAD 0.0009%). This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 309 of the APOB protein (p.Ala309Ser). -

Hypercholesterolemia, autosomal dominant, type B

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Familial hypobetalipoproteinemia 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.080

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Benign

-0.52

CADD

Benign

DANN

Uncertain

0.99

DEOGEN2

Benign

0.018

.;T

Eigen

Benign

0.10

Eigen_PC

Benign

0.037

FATHMM_MKL

Benign

0.58

LIST_S2

Benign

0.68

.;T

M_CAP

Benign

0.017

MetaRNN

Benign

0.24

T;T

MetaSVM

Benign

-0.95

MutationTaster

Benign

0.90

N;N

PrimateAI

Benign

0.29

PROVEAN

Benign

-1.1

N;N

REVEL

Benign

0.15

Sift

Benign

0.37

T;T

Sift4G

Benign

0.21

T;D

Vest4

0.12

MutPred

0.53

Gain of phosphorylation at A309 (P = 0.029);Gain of phosphorylation at A309 (P = 0.029);

MVP

0.58

MPC

0.18

ClinPred

0.87

GERP RS

3.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

gMVP

0.38

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over