2-43846309-C-T

Variant names:

• chr2-43846309-C-T
• rs137854891
• NM_022437.3:c.320C>T

Variant summary

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

The NM_022437.3(ABCG8):​c.320C>T​(p.Ser107Leu) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,856 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ABCG8 NM_022437.3 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.27
• Publications: 0 publications found

Genes affected

ABCG8 (HGNC:13887): (ATP binding cassette subfamily G member 8) The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the White subfamily. The protein encoded by this gene functions to exclude non-cholesterol sterol entry at the intestinal level, promote excretion of cholesterol and sterols into bile, and to facilitate transport of sterols back into the intestinal lumen. It is expressed in a tissue-specific manner in the liver, intestine, and gallbladder. This gene is tandemly arrayed on chromosome 2, in a head-to-head orientation with family member ABCG5. Mutations in this gene may contribute to sterol accumulation and atherosclerosis, and have been observed in patients with sitosterolemia. [provided by RefSeq, Jul 2008]

ABCG8 Gene-Disease associations (from GenCC):

• sitosterolemia

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet, Illumina
• sitosterolemia 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P

ACMG classification

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

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_022437.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABCG8	NM_022437.3	MANE Select	c.320C>T	p.Ser107Leu	missense splice_region	Exon 3 of 13	NP_071882.1
	ABCG8	NM_001357321.2		c.320C>T	p.Ser107Leu	missense splice_region	Exon 3 of 13	NP_001344250.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABCG8	ENST00000272286.4	TSL:1 MANE Select	c.320C>T	p.Ser107Leu	missense splice_region	Exon 3 of 13	ENSP00000272286.2
	ABCG8	ENST00000644611.1		c.332C>T	p.Ser111Leu	missense splice_region	Exon 3 of 9	ENSP00000495423.1
	ABCG8	ENST00000643284.1		n.777C>T		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461856 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727230

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: 26132

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112000

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Sitosterolemia 1 Uncertain:1

Feb 22, 2021

New York Genome Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Cardiovascular phenotype Uncertain:1

Sep 01, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.320C>T (p.S107L) alteration is located in exon 3 (coding exon 3) of the ABCG8 gene. This alteration results from a C to T substitution at nucleotide position 320, causing the serine (S) at amino acid position 107 to be replaced by a leucine (L). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		7.3
PrimateAI	Benign	0.41	T
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		0.75	P
Vest4		0.67
MutPred		0.82		Loss of glycosylation at S107 (P = 0.0466)
MVP		0.98
MPC		0.076
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.88
gMVP		0.62
Mutation Taster		=33/67	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.42		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.26		Position offset: -38
DS_DL_spliceai		0.42		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs137854891; hg19: chr2-44073448;