7-87402256-A-C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PP2 PP3_Strong

The NM_000443.4(ABCB4):c.3680T>G(p.Ile1227Ser) 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 (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: ABCB4 NM_000443.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.32

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 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, 0.948

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ABCB4	NM_000443.4	c.3680T>G	p.Ile1227Ser	missense_variant	28/28	ENST00000649586.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABCB4	ENST00000649586.2	c.3680T>G	p.Ile1227Ser	missense_variant	28/28		NM_000443.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 27, 2022

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. This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1227 of the ABCB4 protein (p.Ile1227Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ABCB4-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Pathogenic	30
Dann	Uncertain	0.99
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Pathogenic	0.30	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D
MetaSVM	Uncertain	0.48	D
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.60	T
Polyphen		0.96	D;.;P;D;.
Vest4		0.91, 0.89, 0.91, 0.91
MutPred		0.84		.;.;Gain of disorder (P = 0.0263);.;.;
MVP		0.94
MPC		0.72
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.93
gMVP		0.96

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr7-87031572;