7-87431528-C-G

Variant names:

• chr7-87431528-C-G
• rs45575636
• NM_000443.4:c.1769G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000443.4(ABCB4):​c.1769G>C​(p.Arg590Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R590Q) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ABCB4 NM_000443.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.86
• Publications: 36 publications found

Genes affected

ABCB4 (HGNC:45): (ATP binding cassette subfamily B member 4) The membrane-associated 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 MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance as well as antigen presentation. This gene encodes a full transporter and member of the p-glycoprotein family of membrane proteins with phosphatidylcholine as its substrate. The function of this protein has not yet been determined; however, it may involve transport of phospholipids from liver hepatocytes into bile. Alternative splicing of this gene results in several products of undetermined function. [provided by RefSeq, Jul 2008]

ABCB4 Gene-Disease associations (from GenCC):

• progressive familial intrahepatic cholestasis type 3

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
• gallbladder disease 1

  Inheritance: SD, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Orphanet
• pancreatitis

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000443.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the ABCB4 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 32 curated pathogenic missense variants (we use a threshold of 10). The gene has 6 curated benign missense variants. Gene score misZ: 1.9749 (below the threshold of 3.09). Trascript score misZ: 3.5425 (above the threshold of 3.09). GenCC associations: The gene is linked to gallbladder disease 1, progressive familial intrahepatic cholestasis type 3, pancreatitis.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.945

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCB4	NM_000443.4	c.1769G>C	p.Arg590Pro	missense_variant	Exon 15 of 28	ENST00000649586.2	NP_000434.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCB4	ENST00000649586.2	c.1769G>C	p.Arg590Pro	missense_variant	Exon 15 of 28		NM_000443.4	ENSP00000496956.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251094 AF XY: 0.00

Gnomad AFR exome AF: 0.00

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: 0.00000882

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Oct 28, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 590 of the ABCB4 protein (p.Arg590Pro). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with ABCB4-related conditions. Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt ABCB4 protein function with a positive predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	.;.;D;.;.
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.98	.;D;D;D;.
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.94	D;D;D;D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	4.0	H;H;H;H;H
PhyloP100		7.9
PrimateAI	Uncertain	0.66	T
PROVEAN	Pathogenic	-6.3	.;D;D;D;D
REVEL	Pathogenic	0.86
Sift	Uncertain	0.0010	.;D;D;D;D
Sift4G	Pathogenic	0.0010	.;D;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.98, 0.95, 0.97, 0.97
MutPred		0.66		Loss of MoRF binding (P = 0.005);Loss of MoRF binding (P = 0.005);Loss of MoRF binding (P = 0.005);Loss of MoRF binding (P = 0.005);Loss of MoRF binding (P = 0.005);
MVP		0.92
MPC		0.91
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.95
gMVP		0.95
Mutation Taster		=11/89	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: rs45575636; hg19: chr7-87060844;