NM_001646.3:c.245T>G

Variant names:

• chr19-44945166-T-G
• rs776657518
• NM_001646.3:c.245T>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001646.3(APOC4):​c.245T>G​(p.Met82Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,922 control chromosomes in the GnomAD database, with no homozygous occurrence. 11/19 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M82V) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: APOC4 NM_001646.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.13
• Publications: 1 publications found

Genes affected

APOC4 (HGNC:611): (apolipoprotein C4) This gene encodes a lipid-binding protein belonging to the apolipoprotein gene family. The protein is thought to play a role in lipid metabolism. Polymorphisms in this gene may influence circulating lipid levels and may be associated with coronary artery disease risk. 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 downstream apolipoprotein C-II (APOC2) 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

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001646.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APOC4	NM_001646.3	MANE Select	c.245T>G	p.Met82Arg	missense	Exon 3 of 3	NP_001637.1	P55056
	APOC4-APOC2	NR_037932.1		n.285T>G		non_coding_transcript_exon	Exon 3 of 6

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APOC4	ENST00000592954.2	TSL:1 MANE Select	c.245T>G	p.Met82Arg	missense	Exon 3 of 3	ENSP00000468236.1	P55056
	APOC4-APOC2	ENST00000589057.5	TSL:5	c.218+276T>G		intron	N/A	ENSP00000468139.1	K7ER74
	APOC4	ENST00000896758.1		c.266T>G	p.Met89Arg	missense	Exon 3 of 3	ENSP00000566817.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152142 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251260 AF XY: 0.00

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461780 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727210

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

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44716

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26122

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53372

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111980

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152142 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 74324

African (AFR) AF: 0.0000241 AC: 1 AN: 41430

American (AMR) AF: 0.00 AC: 0 AN: 15270

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68026

Other (OTH) AF: 0.00 AC: 0 AN: 2086

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000189

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Benign	-0.17	T
BayesDel_noAF	Benign	-0.30
CADD	Benign	18
DANN	Benign	0.94
DEOGEN2	Benign	0.18	T
Eigen	Benign	0.10
Eigen_PC	Benign	0.046
FATHMM_MKL	Benign	0.73	D
M_CAP	Benign	0.025	T
MetaRNN	Uncertain	0.67	D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.2	L
PhyloP100		3.1
Sift4G	Uncertain	0.0090	D
Polyphen		0.97	D
Vest4		0.66
MutPred		0.51		Loss of helix (P = 0.0167)
MVP		0.38
ClinPred		0.27	T
GERP RS		4.0
Varity_R		0.60
gMVP		0.44
Mutation Taster		=84/16	polymorphism

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

Other links and lift over

dbSNP: rs776657518; hg19: chr19-45448423;