chr2-21001501-T-C

Position:

• chr2-21001501-T-C

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS2

The NM_000384.3(APOB):​c.*229A>G variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00132 in 511,510 control chromosomes in the GnomAD database, including 6 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0019 (2 hom., cov: 32)
  • Exomes 𝑓: 0.0011 (4 hom.)
• Consequence: APOB NM_000384.3 3_prime_UTR
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:2
• Conservation: PhyloP100: 0.812

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 Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.67).
• BP6: Variant 2-21001501-T-C is Benign according to our data. Variant chr2-21001501-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 334057.We mark this variant Likely_benign, oryginal submissions are: {Benign=1, Likely_benign=1, Uncertain_significance=1}.
• BS2: High Homozygotes in GnomAd4 at 2 SD gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APOB	NM_000384.3	c.*229A>G		3_prime_UTR_variant	29/29	ENST00000233242.5	NP_000375.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APOB	ENST00000233242	c.*229A>G		3_prime_UTR_variant	29/29	1	NM_000384.3	ENSP00000233242.1

Frequencies

GnomAD3 genomes AF: 0.00191 AC: 290 AN: 152138 Hom.: 2 Cov.: 32

Gnomad AFR AF: 0.00249

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00767

Gnomad ASJ AF: 0.00346

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000764

Gnomad OTH AF: 0.00288

GnomAD4 exome AF: 0.00106 AC: 382 AN: 359254 Hom.: 4 Cov.: 3 AF XY: 0.000982 AC XY: 186 AN XY: 189420

Gnomad4 AFR exome AF: 0.00176

Gnomad4 AMR exome AF: 0.00436

Gnomad4 ASJ exome AF: 0.00514

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000296

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000841

Gnomad4 OTH exome AF: 0.00260

GnomAD4 genome AF: 0.00191 AC: 291 AN: 152256 Hom.: 2 Cov.: 32 AF XY: 0.00203 AC XY: 151 AN XY: 74444

Gnomad4 AFR AF: 0.00250

Gnomad4 AMR AF: 0.00766

Gnomad4 ASJ AF: 0.00346

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000764

Gnomad4 OTH AF: 0.00285

Alfa AF: 0.00139 Hom.: 0

Bravo AF: 0.00275

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial hypobetalipoproteinemia 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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. -

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

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 17, 2023

- -

Hypercholesterolemia, autosomal dominant, type B Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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 and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.67
CADD	Benign	11
DANN	Benign	0.86
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

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: rs72654430; hg19: chr2-21224373;