chr2-21029632-A-G

Variant names:

• chr2-21029632-A-G
• rs374552390
• NM_000384.3:c.1617+7T>C

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_Strong BP6

The NM_000384.3(APOB):​c.1617+7T>C variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000397 in 1,613,978 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000042 (0 hom.)
• Consequence: APOB NM_000384.3 splice_region, intron
• Scores: Splicing: ADA: 0.0002073
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 0.0940
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BP6: Variant 2-21029632-A-G is Benign according to our data. Variant chr2-21029632-A-G is described in CliVar as Conflicting_classifications_of_pathogenicity. Clinvar id is 548040. Variant chr2-21029632-A-G is described in CliVar as Conflicting_classifications_of_pathogenicity. Clinvar id is 548040. Variant chr2-21029632-A-G is described in CliVar as Conflicting_classifications_of_pathogenicity. Clinvar id is 548040.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APOB	NM_000384.3	c.1617+7T>C		splice_region_variant, intron_variant	Intron 12 of 28	ENST00000233242.5	NP_000375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APOB	ENST00000233242.5	c.1617+7T>C		splice_region_variant, intron_variant	Intron 12 of 28	1	NM_000384.3	ENSP00000233242.1
APOB	ENST00000399256.4	c.1617+7T>C		splice_region_variant, intron_variant	Intron 12 of 16	1		ENSP00000382200.4
APOB	ENST00000673739.2	n.*923+7T>C		splice_region_variant, intron_variant	Intron 11 of 24			ENSP00000501110.2
APOB	ENST00000673882.2	n.*923+7T>C		splice_region_variant, intron_variant	Intron 11 of 22			ENSP00000501253.2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152162 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000478 AC: 12 AN: 251080 AF XY: 0.0000442

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000867

Gnomad ASJ exome AF: 0.0000993

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000705

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000424 AC: 62 AN: 1461816 Hom.: 0 Cov.: 32 AF XY: 0.0000426 AC XY: 31 AN XY: 727210

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.000134 AC: 6 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.0000562 AC: 3 AN: 53372

Middle Eastern (MID) AF: 0.000173 AC: 1 AN: 5768

European-Non Finnish (NFE) AF: 0.0000378 AC: 42 AN: 1111990

Other (OTH) AF: 0.000166 AC: 10 AN: 60394

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152162 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74350

African (AFR) AF: 0.00 AC: 0 AN: 41424

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.0000987 Hom.: 0

Bravo AF: 0.0000378

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hypercholesterolemia, autosomal dominant, type B Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

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

- -

Familial hypobetalipoproteinemia 1 Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

not specified Benign:1

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

BP6 -

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

Dec 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

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	1.9
DANN	Benign	0.66
PhyloP100		0.094
Mutation Taster		=100/0	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00021
dbscSNV1_RF	Benign	0.0
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

Other links and lift over

dbSNP: rs374552390; hg19: chr2-21252504;