NM_000384.3:c.12739C>T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Strong

The NM_000384.3(APOB):c.12739C>T(p.Gln4247*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000174 in 1,613,574 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. Q4247Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000018 ( 0 hom. )

Consequence

APOB
NM_000384.3 stop_gained

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 2.80

Publications

2 publications found

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 Gene-Disease associations (from GenCC):

hypercholesterolemia, autosomal dominant, type B
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
familial hypobetalipoproteinemia 1
Inheritance: AR, AD, SD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen
homozygous familial hypercholesterolemia
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

APOB links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 11 pathogenic variants in the truncated region.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APOB	NM_000384.3 link	c.12739C>T	p.Gln4247*	stop_gained	Exon 29 of 29	ENST00000233242.5	NP_000375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APOB	ENST00000233242.5 link	c.12739C>T	p.Gln4247*	stop_gained	Exon 29 of 29	1	NM_000384.3	ENSP00000233242.1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152086

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000319

AC:

AN:

250738

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000597

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000882

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.0000178

AC:

AN:

1461488

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727062

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33424

American (AMR)

AF:

0.00

AC:

AN:

44660

Ashkenazi Jewish (ASJ)

AF:

0.000651

AC:

AN:

26120

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86218

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53394

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.00000360

AC:

AN:

1111836

Other (OTH)

AF:

0.0000828

AC:

AN:

60376

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152086

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74276

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41406

American (AMR)

AF:

0.00

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.000288

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68014

Other (OTH)

AF:

0.00

AC:

AN:

2090

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00000037155), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000113

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

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

Uncertain:2

Nov 12, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Gln4247*) in the APOB gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 317 amino acid(s) of the APOB protein. This variant is present in population databases (no rsID available, gnomAD 0.06%). This premature translational stop signal has been observed in individual(s) with hypercholesterolemia (PMID: 33418990). ClinVar contains an entry for this variant (Variation ID: 544074). This variant disrupts a region of the APOB protein in which other variant(s) (p.Tyr4380*) have been observed in individuals with APOB-related conditions (Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. 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. -

not provided

Uncertain:1

Aug 04, 2021

AiLife Diagnostics, AiLife Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiovascular phenotype

Uncertain:1

May 29, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Q4247* variant (also known as c.12739C>T), located in coding exon 29 of the APOB gene, results from a C to T substitution at nucleotide position 12739. This changes the amino acid from a glutamine to a stop codon within coding exon 29. This alteration has been reported in a familial hypercholesterolemia (FH) cohort (Meshkov A et al. Genes (Basel), 2021 01;12:). This alteration is expected to result in premature protein truncation or nonsense-mediated mRNA decay. However, loss of function of APOB-related familial hypercholesterolemia (FH) has not been clearly established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.38

BayesDel_noAF

Pathogenic

0.31

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Pathogenic

0.89

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Uncertain

0.91

PhyloP100

2.8

Vest4

0.71

GERP RS

3.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Mutation Taster

=29/171

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over