chr7-87439761-G-T

Variant names:

• chr7-87439761-G-T
• rs121918441
• NM_000443.4:c.1637C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PP2 PP3_Strong

The NM_000443.4(ABCB4):​c.1637C>A​(p.Ala546Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000752 in 1,461,876 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: ABCB4 NM_000443.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:3
• Conservation: PhyloP100: 8.10
• Publications: 4 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), Orphanet, ClinGen
• gallbladder disease 1

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

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000443.4
• 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 pancreatitis, gallbladder disease 1, progressive familial intrahepatic cholestasis type 3.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.985

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000443.4. 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
	ABCB4	NM_000443.4	MANE Select	c.1637C>A	p.Ala546Asp	missense	Exon 14 of 28	NP_000434.1	P21439-2
	ABCB4	NM_018849.3		c.1637C>A	p.Ala546Asp	missense	Exon 14 of 28	NP_061337.1	P21439-1
	ABCB4	NM_018850.3		c.1637C>A	p.Ala546Asp	missense	Exon 14 of 27	NP_061338.1	P21439-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ABCB4	ENST00000649586.2	MANE Select	c.1637C>A	p.Ala546Asp	missense	Exon 14 of 28	ENSP00000496956.2	P21439-2
	ABCB4	ENST00000265723.8	TSL:1	c.1637C>A	p.Ala546Asp	missense	Exon 14 of 28	ENSP00000265723.4	P21439-1
	ABCB4	ENST00000359206.8	TSL:1	c.1637C>A	p.Ala546Asp	missense	Exon 14 of 28	ENSP00000352135.3	P21439-2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251282 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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461876 Hom.: 0 Cov.: 32 AF XY: 0.00000688 AC XY: 5 AN XY: 727242

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: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

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

European-Non Finnish (NFE) AF: 0.00000989 AC: 11 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	ABCB4-related disorder (1)
1	-	-	Cholestasis, intrahepatic, of pregnancy, 3 (1)
-	1	-	not provided (1)
-	1	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.75	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.5	H
PhyloP100		8.1
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.4	D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.89		Loss of MoRF binding (P = 0.0522)
MVP		0.96
MPC		1.2
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.99
gMVP		0.99
Mutation Taster		=0/100	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: rs121918441; hg19: chr7-87069077; COSMIC: COSV55939902;