Genetic Variant APOB:c.122-6C>T (chr2-21042482-G-A) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The NM_000384.3(APOB):c.122-6C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,458,788 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

APOB
NM_000384.3 splice_region, intron

Scores

Splicing: ADA: 0.00002048

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.68

Publications

0 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: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.82).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APOB	NM_000384.3 link	c.122-6C>T		splice_region_variant, intron_variant	Intron 2 of 28	ENST00000233242.5	NP_000375.3	P04114Q7Z7Q0Q59HB3

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein	UniProt
APOB	ENST00000233242.5 link	c.122-6C>T	splice_region_variant, intron_variant	Intron 2 of 28	1	NM_000384.3	ENSP00000233242.1	P04114
APOB	ENST00000399256.4 link	c.122-6C>T	splice_region_variant, intron_variant	Intron 2 of 16	1		ENSP00000382200.4	A8MUN2
APOB	ENST00000673739.2 link	n.122-6C>T	splice_region_variant, intron_variant	Intron 2 of 24			ENSP00000501110.2	A0A669KB70
APOB	ENST00000673882.2 link	n.122-6C>T	splice_region_variant, intron_variant	Intron 2 of 22			ENSP00000501253.2	A0A669KB70

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1458788

Hom.:

Cov.:

AF XY:

0.00000276

AC XY:

AN XY:

725908

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33416

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26124

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39686

South Asian (SAS)

AF:

0.00

AC:

AN:

86188

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5762

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1109176

Other (OTH)

AF:

0.00

AC:

AN:

60302

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.425

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

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Hypercholesterolemia, familial, 1

Uncertain:1

Jan 02, 2018

Robarts Research Institute, Western University

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.82

CADD

Benign

9.5

(source)

DANN

Benign

0.72

PhyloP100

1.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000020

dbscSNV1_RF

Benign

0.010

SpliceAI score (max)

0.16

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over