chr12-21860987-G-A

Variant names:

• chr12-21860987-G-A
• rs997660720
• NM_020297.4:c.2408C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_020297.4(ABCC9):​c.2408C>T​(p.Thr803Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,460,912 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 (★★). Synonymous variant affecting the same amino acid position (i.e. T803T) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: ABCC9 NM_020297.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.88
• Publications: 0 publications found

Genes affected

ABCC9 (HGNC:60): (ATP binding cassette subfamily C member 9) The 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 MRP subfamily which is involved in multi-drug resistance. This protein is thought to form ATP-sensitive potassium channels in cardiac, skeletal, and vascular and non-vascular smooth muscle. Protein structure suggests a role as the drug-binding channel-modulating subunit of the extra-pancreatic ATP-sensitive potassium channels. Mutations in this gene are associated with cardiomyopathy dilated type 1O. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Apr 2011]

ABCC9 Gene-Disease associations (from GenCC):

• hypertrichotic osteochondrodysplasia Cantu type

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• dilated cardiomyopathy 1O

  Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: Illumina, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• intellectual disability and myopathy syndrome

  Inheritance: AR Classification: MODERATE, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• acromegaloid facial appearance syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hypertrichosis-acromegaloid facial appearance syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Brugada syndrome

  Inheritance: AD Classification: LIMITED Submitted by: Genomics England PanelApp
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• atrial fibrillation, familial, 12

  Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

ENSG00000257022 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.986

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCC9	NM_020297.4	c.2408C>T	p.Thr803Ile	missense_variant	Exon 21 of 40	ENST00000261200.9	NP_064693.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCC9	ENST00000261200.9	c.2408C>T	p.Thr803Ile	missense_variant	Exon 21 of 40	5	NM_020297.4	ENSP00000261200.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460912 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 726814

African (AFR) AF: 0.00 AC: 0 AN: 33436

American (AMR) AF: 0.00 AC: 0 AN: 44688

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39660

South Asian (SAS) AF: 0.00 AC: 0 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53228

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111430

Other (OTH) AF: 0.00 AC: 0 AN: 60358

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000151

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Dilated cardiomyopathy 1O Uncertain:1

Aug 23, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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) performed at Invitae indicates that this missense variant is expected to disrupt ABCC9 protein function. ClinVar contains an entry for this variant (Variation ID: 410816). This variant has not been reported in the literature in individuals affected with ABCC9-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 803 of the ABCC9 protein (p.Thr803Ile). -

ABCC9-related disorder Uncertain:1

Sep 14, 2022

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The ABCC9 c.2408C>T variant is predicted to result in the amino acid substitution p.Thr803Ile. To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. 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	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	.;.;D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	H;.;H
PhyloP100		9.9
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-5.5	D;D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D;D
Sift4G	Uncertain	0.013	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.94
MutPred		0.94		Loss of disorder (P = 0.0663);.;Loss of disorder (P = 0.0663);
MVP		0.98
MPC		1.8
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.84
gMVP		0.76
Mutation Taster		=3/97	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs997660720; hg19: chr12-22013921;