rs193922408

Positions:

• chr11-17393122-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000352.6(ABCC8):​c.4615G>A​(p.Val1539Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,530 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: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ABCC8 NM_000352.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:6
• Conservation: PhyloP100: 7.58

Genes affected

ABCC8 (HGNC:59): (ATP binding cassette subfamily C member 8) 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 functions as a modulator of ATP-sensitive potassium channels and insulin release. Mutations in the ABCC8 gene and deficiencies in the encoded protein have been observed in patients with hyperinsulinemic hypoglycemia of infancy, an autosomal recessive disorder of unregulated and high insulin secretion. Mutations have also been associated with non-insulin-dependent diabetes mellitus type II, an autosomal dominant disease of defective insulin secretion. Alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Jul 2020]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000352.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.841

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ABCC8	NM_000352.6	c.4615G>A	p.Val1539Met	missense_variant	39/39	ENST00000389817.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ABCC8	ENST00000389817.8	c.4615G>A	p.Val1539Met	missense_variant	39/39	1	NM_000352.6	P4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461530 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727066

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: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000655 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 29, 2019	Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Feb 05, 2022	This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 1539 of the ABCC8 protein (p.Val1539Met). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of neonatal diabetes mellitus (PMID: 32027066). This variant is also known as c.4618G>A, p.(Val1540Met). ClinVar contains an entry for this variant (Variation ID: 35623). 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 not expected to disrupt ABCC8 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. -

Permanent neonatal diabetes mellitus Pathogenic:1

Likely pathogenic, flagged submission

clinical testing

Genetic Services Laboratory, University of Chicago

Apr 04, 2017

- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

May 04, 2023

Variant summary: ABCC8 c.4615G>A (p.Val1539Met) results in a conservative amino acid change located in the ABC transporter-like, ATP-binding domain (IPR003439) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 250682 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.4615G>A has been reported in the literature in an individual affected with late onset diabetes/hyperinsulinism (de Franco_2020). This report does not provide unequivocal conclusions about association of the variant with Neonatal Diabetes Mellitus. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 32027066). Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classifed the variant as VUS (n=3) and likely pathogenic (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Maturity onset diabetes mellitus in young Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

Mutations in ABCC8 gene are associated with both neonatal diabetes mellitus as well as MODY. Patients with this mutation may have a better response to sulfonylureas. However, no sufficient evidence is found to ascertain the role of this particular variant (rs193922408 ) in MODY yet. -

Hyperinsulinemic hypoglycemia, familial, 1 Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Counsyl

Sep 19, 2017

- -

Transitory neonatal diabetes mellitus Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

Mutations in ABCC8 gene are associated with both neonatal diabetes mellitus as well as MODY. Patients with this mutation may have a better response to sulfonylureas. However, no sufficient evidence is found to ascertain the role of this particular variant (rs193922408 ) in neonatal diabetes yet. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.52	.;.;D;.;.;.;.;.
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.97	D;.;D;D;D;D;D;D
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.061	D
MutationAssessor	Benign	0.20	.;.;N;.;.;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Uncertain	-2.4	.;.;N;N;.;.;.;.
REVEL	Uncertain	0.64
Sift	Uncertain	0.0010	.;.;D;D;.;.;.;.
Sift4G	Uncertain	0.018	.;.;D;D;.;.;.;.
Polyphen		0.99	.;.;D;.;.;.;.;.
Vest4		0.78, 0.78
MutPred		0.57		.;.;Gain of catalytic residue at V1539 (P = 0.0098);.;.;.;Gain of catalytic residue at V1539 (P = 0.0098);.;
MVP		0.91
MPC		1.6
ClinPred		0.94	D
GERP RS		5.2
Varity_R		0.62
gMVP		0.80

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs193922408; hg19: chr11-17414669;