chr7-87453050-G-C

Position:

• chr7-87453050-G-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.430C>G​(p.Arg144Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,838 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 (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ABCB4 NM_000443.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.81

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a helix (size 51) in uniprot entity MDR3_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000443.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), ABCB4. . Gene score misZ 1.9749 (greater than the threshold 3.09). Trascript score misZ 3.5425 (greater than threshold 3.09). GenCC has associacion of gene with pancreatitis, low phospholipid associated cholelithiasis, progressive familial intrahepatic cholestasis type 3.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.96

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABCB4	NM_000443.4	c.430C>G	p.Arg144Gly	missense_variant	6/28	ENST00000649586.2	NP_000434.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABCB4	ENST00000649586.2	c.430C>G	p.Arg144Gly	missense_variant	6/28		NM_000443.4	ENSP00000496956.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461838 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727216

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

May 21, 2024

Variant summary: ABCB4 c.430C>G (p.Arg144Gly) results in a non-conservative amino acid change located in the ABC transporter type 1, transmembrane domain (IPR011527) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251350 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.430C>G in individuals affected with Familial Intrahepatic Cholestasis and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.61
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	.;.;D;.;.
Eigen	Pathogenic	0.79
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	.;D;D;D;.
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.96	D;D;D;D;D
MetaSVM	Uncertain	0.75	D
MutationAssessor	Pathogenic	4.3	H;H;H;H;H
PrimateAI	Benign	0.47	T
PROVEAN	Pathogenic	-5.6	.;D;D;D;D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	.;D;D;D;D
Sift4G	Uncertain	0.0020	.;D;D;D;D
Polyphen		1.0	D;.;D;D;.
Vest4		0.86, 0.86, 0.85, 0.86
MutPred		0.82		Loss of MoRF binding (P = 0.028);Loss of MoRF binding (P = 0.028);Loss of MoRF binding (P = 0.028);Loss of MoRF binding (P = 0.028);Loss of MoRF binding (P = 0.028);
MVP		0.94
MPC		1.1
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.92
gMVP		0.98

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

Other links and lift over

dbSNP: rs72552780; hg19: chr7-87082366;