chr19-44948488-C-T

Variant names:

• chr19-44948488-C-T
• rs202190413
• NM_000483.5:c.10C>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000483.5(APOC2):​c.10C>T​(p.Arg4*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000806 in 1,613,892 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: APOC2 NM_000483.5 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 0.999

Genes affected

APOC2 (HGNC:609): (apolipoprotein C2) This gene encodes a lipid-binding protein belonging to the apolipoprotein gene family. The protein is secreted in plasma where it is a component of very low density lipoprotein. This protein activates the enzyme lipoprotein lipase, which hydrolyzes triglycerides and thus provides free fatty acids for cells. Mutations in this gene cause hyperlipoproteinemia type IB, characterized by hypertriglyceridemia, xanthomas, and increased risk of pancreatitis and early atherosclerosis. This gene is present in a cluster with other related apolipoprotein genes on chromosome 19. Naturally occurring read-through transcription exists between this gene and the neighboring upstream apolipoprotein C-IV (APOC4) gene. [provided by RefSeq, Mar 2011]

APOC4-APOC2 (HGNC:44426): (APOC4-APOC2 readthrough (NMD candidate)) This locus represents naturally occurring read-through transcription between the neighboring apolipoprotein C-IV (APOC4) and apolipoprotein C-II (APOC2) genes on chromosome 19. The read-through transcript is a candidate for nonsense-mediated mRNA decay (NMD), and is thus unlikely to produce a protein product. [provided by RefSeq, Mar 2011]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 5 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 19-44948488-C-T is Pathogenic according to our data. Variant chr19-44948488-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1374052.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr19-44948488-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APOC2	NM_000483.5	c.10C>T	p.Arg4*	stop_gained	Exon 2 of 4	ENST00000252490.7	NP_000474.2
APOC4-APOC2	NR_037932.1	n.1217C>T		non_coding_transcript_exon_variant	Exon 4 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APOC2	ENST00000252490.7	c.10C>T	p.Arg4*	stop_gained	Exon 2 of 4	2	NM_000483.5	ENSP00000252490.5
APOC4-APOC2	ENST00000589057.5	c.241C>T	p.Arg81*	stop_gained	Exon 3 of 5	5		ENSP00000468139.1

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 152058 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000278 AC: 7 AN: 251490 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135920

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000109

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: 0.00000752 AC: 11 AN: 1461834 Hom.: 0 Cov.: 32 AF XY: 0.00000963 AC XY: 7 AN XY: 727216

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 152058 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74248

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ExAC AF: 0.0000412 AC: 5

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

May 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg4*) in the APOC2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in APOC2 are known to be pathogenic (PMID: 1569385, 1971748, 26772541). This variant is present in population databases (rs202190413, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with apolipoprotein C-II deficiency (PMID: 1569385). This variant is also known as ApoC-II Paris2. ClinVar contains an entry for this variant (Variation ID: 1374052). For these reasons, this variant has been classified as Pathogenic. -

Jul 14, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 34426522, 1569385) -

Familial apolipoprotein C-II deficiency Pathogenic:1

May 20, 2023

Neuberg Centre For Genomic Medicine, NCGM

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The observed stop gained variant c.10C>T(p.Arg4Ter) in APOC2 gene has been reported in homozygous state in an individual with apolipoprotein C-II deficiency (Parrott CL, et al., 1992). The c.10C>T variant has 0.003% allele frequency in gnomAD Exomes. This variant has been reported to the ClinVar database as Pathogenic. Computational evidence (Mutation Taster - Disease causing) predicts damaging effect on protein structure and function for this variant.This variant is predicted to cause loss of normal protein function through protein truncation. Loss of function variants have been previously reported to be disease causing (Jiang J, et al.., 2016). For these reasons, this variant has been classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Uncertain	0.020
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Benign	0.032
Eigen_PC	Benign	-0.37
FATHMM_MKL	Benign	0.090	N
Vest4		0.14
GERP RS		0.58
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs202190413; hg19: chr19-45451745; COSMIC: COSV99377049; COSMIC: COSV99377049;