2-21035681-T-C

Variant names:

• chr2-21035681-T-C
• rs758838678
• NM_000384.3:c.721A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000384.3(APOB):​c.721A>G​(p.Ser241Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,780 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. S241C) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: APOB NM_000384.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.57
• 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: ClinGen, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• familial hypobetalipoproteinemia 1

  Inheritance: AR, SD, AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp
• homozygous familial hypercholesterolemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.879

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000384.3. 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
	APOB	NM_000384.3	MANE Select	c.721A>G	p.Ser241Gly	missense	Exon 7 of 29	NP_000375.3	P04114

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APOB	ENST00000233242.5	TSL:1 MANE Select	c.721A>G	p.Ser241Gly	missense	Exon 7 of 29	ENSP00000233242.1	P04114
	APOB	ENST00000399256.4	TSL:1	c.721A>G	p.Ser241Gly	missense	Exon 7 of 17	ENSP00000382200.4	A8MUN2
	APOB	ENST00000673739.2		n.*27A>G		non_coding_transcript_exon	Exon 6 of 25	ENSP00000501110.2	A0A669KB70

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461780 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727192

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

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5686

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.030	T
BayesDel_noAF	Benign	-0.19
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.15	T
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Benign	0.83	T
M_CAP	Benign	0.050	D
MetaRNN	Pathogenic	0.88	D
MetaSVM	Benign	-1.1	T
PhyloP100		7.6
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-3.0	D
REVEL	Uncertain	0.44
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0040	D
Vest4		0.74
MutPred		0.73		Loss of stability (P = 0.0565)
MVP		0.69
MPC		0.11
ClinPred		1.0	D
GERP RS		5.7
gMVP		0.76
Mutation Taster		=31/69	disease causing

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: rs758838678; hg19: chr2-21258553;