7-87402172-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1PM2PP2PP3

The NM_000443.4(ABCB4):c.3764C>T(p.Thr1255Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000335 in 1,614,060 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 Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T1255T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00015 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

ABCB4
NM_000443.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 6.80

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM1

In a domain ABC transporter 2 (size 245) in uniprot entity MDR3_HUMAN there are 11 pathogenic changes around while only 2 benign (85%) in NM_000443.4

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant where missense usually causes diseases, ABCB4

PP3

MetaRNN computational evidence supports a deleterious effect, 0.838

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ABCB4	NM_000443.4 linkuse as main transcript	c.3764C>T	p.Thr1255Met	missense_variant	28/28	ENST00000649586.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABCB4	ENST00000649586.2 linkuse as main transcript	c.3764C>T	p.Thr1255Met	missense_variant	28/28		NM_000443.4	P1	P21439-2

Frequencies

GnomAD3 genomes

AF:

0.000151

AC:

AN:

152162

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000507

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000477

AC:

AN:

251396

Hom.:

AF XY:

0.0000515

AC XY:

AN XY:

135870

show subpopulations

Gnomad AFR exome

AF:

0.000492

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000212

AC:

AN:

1461780

Hom.:

Cov.:

AF XY:

0.0000220

AC XY:

AN XY:

727186

show subpopulations

Gnomad4 AFR exome

AF:

0.000597

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.000151

AC:

AN:

152280

Hom.:

Cov.:

AF XY:

0.000188

AC XY:

AN XY:

74446

show subpopulations

Gnomad4 AFR

AF:

0.000505

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.000215

ESP6500AA

AF:

0.000908

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	May 09, 2023	PM2 -
Uncertain significance, no assertion criteria provided	clinical testing	Department of Pathology and Laboratory Medicine, Sinai Health System	-	The ABCB4 p.Thr1255Met variant was not identified in the literature nor was it identified in ClinVar, Cosmic or LOVD 3.0. The variant was identified in dbSNP (ID: rs147577035) and was also found in control databases in 16 of 282790 chromosomes at a frequency of 0.000057 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: African in 12 of 24968 chromosomes (freq: 0.000481), Latino in 2 of 35440 chromosomes (freq: 0.000056), South Asian in 1 of 30616 chromosomes (freq: 0.000033) and European (non-Finnish) in 1 of 129108 chromosomes (freq: 0.000008), while the variant was not observed in the Ashkenazi Jewish, East Asian, European (Finnish) and Other populations. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. The p.Thr1255 residue is conserved in mammals but not in more distantly related organisms, and four out of five computational analyses (PolyPhen-2, SIFT, BLOSUM, MutationTaster) suggest that the variant may impact the protein; however, this information is not predictive enough to assume pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 20, 2024	This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 1255 of the ABCB4 protein (p.Thr1255Met). This variant is present in population databases (rs147577035, gnomAD 0.05%). This missense change has been observed in individual(s) with ABCB4-related conditions (PMID: 35894240). This variant is also known as c.3785C>T (p.Thr1262Met). ClinVar contains an entry for this variant (Variation ID: 1049446). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on ABCB4 protein function. 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. -

ABCB4-related disorder

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jul 31, 2023

The ABCB4 c.3764C>T variant is predicted to result in the amino acid substitution p.Thr1255Met. This variant, also known as c.3785C>T (p.Thr1262Met), was reported in the compound heterozygous state in an individual with adult-onset liver disease (Nayagam et al 2022. PubMed ID: 35894240 Table S1). This variant is reported in 0.048% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/7-87031488-G-A). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Benign

-0.013

BayesDel_noAF

Uncertain

0.090

Cadd

Uncertain

Dann

Pathogenic

1.0

Eigen

Pathogenic

0.76

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.97

M_CAP

Uncertain

0.20

MetaRNN

Pathogenic

0.84

D;D;D;D;D

MetaSVM

Uncertain

0.26

MutationTaster

Benign

1.0

D;D;D;D;D

PrimateAI

Uncertain

0.54

Polyphen

1.0

D;.;D;D;.

Vest4

0.66, 0.58, 0.67, 0.67

MVP

0.88

MPC

0.94

ClinPred

0.99

GERP RS

5.3

Varity_R

0.43

gMVP

0.74

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over