NM_000352.6:c.1970G>A

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_000352.6(ABCC8):c.1970G>A(p.Arg657Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,614,134 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

ABCC8
NM_000352.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:8

Conservation

PhyloP100: 0.854

Variant links:

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]

ABCC8 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.08768016).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCC8	NM_000352.6 link	c.1970G>A	p.Arg657Gln	missense_variant	Exon 14 of 39	ENST00000389817.8	NP_000343.2	Q09428-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCC8	ENST00000389817.8 link	c.1970G>A	p.Arg657Gln	missense_variant	Exon 14 of 39	1	NM_000352.6	ENSP00000374467.4		Q09428-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152194

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.00000797

AC:

AN:

251014

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135740

show subpopulations

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461822

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727216

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000135

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152312

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74482

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.0000540

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Dec 04, 2022

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: ABCC8 c.1970G>A (p.Arg657Gln) results in a conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251014 control chromosomes. c.1970G>A has been reported in the literature as a heterozygous maternally inherited genotype in at-least one individual affected with Congenital hyperinsulinism of infancy (CHI) (example, Rozenkova_2015). It is not specified whether this individual had a diffuse or a focal lesion and a second paternally in inherited variant supporting a diffuse outcome is also not reported. Furthermore, the maternal inheritance of this variant rules out the possibility of a focal histology. These report(s) do not provide unequivocal conclusions about association of the variant with Familial Hyperinsulinism. At least one publication reports experimental evidence evaluating an impact on protein function (Rozenkova_2015). The most pronounced variant effect results in approximately 41% decrease in function of mutant K-ATP channels in-vitro. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as uncertain significance citing an overlapping evidence utilized in the context of this evaluation. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Type 2 diabetes mellitus

Uncertain:1

Jul 29, 2021

New York Genome Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The heterozygous c.1970G>A (p.Arg657Gln) missense variant identified in the ABCC8 gene has been reported as heterozygous in an individual affected with congenital hyperinsulinism of infancy [PMID: 26431509]. In vitro functional analysis was suggestive of a residual activation by diazoxide incorrespondence to the patient’s phenotype [41% decrease in activity; PMID: 26431509]. The variant has 0.00002628 allele frequency in the gnomAD(v3) database (4out of 152194 heterozygous alleles, no homozygotes) suggesting it is not a common benign variant in the populations represented in that database. This variant hasbeen reported in the ClinVar database as variant of uncertain significance [Variation ID:552764]. The variant affects a weakly conserved residue. In silico tools provide conflicting predictions about potential pathogenicity of this variant (CADD score = 16.81, REVEL score = 0.154). Due to the lack of compelling evidence for its pathogenicity, the heterozygous c.1970G>A (p.Arg657Gln) missense variant identified in the ABCC8 gene is reported as a Variant of UncertainSignificance. -

Inborn genetic diseases

Uncertain:1

Jul 25, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1970G>A (p.R657Q) alteration is located in exon 14 (coding exon 14) of the ABCC8 gene. This alteration results from a G to A substitution at nucleotide position 1970, causing the arginine (R) at amino acid position 657 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Type 2 diabetes mellitus;C0271714:Leucine-induced hypoglycemia;C1835887:Diabetes mellitus, transient neonatal, 2;C2931832:Hyperinsulinemic hypoglycemia, familial, 1;C5394303:Diabetes mellitus, permanent neonatal 3

Uncertain:1

May 12, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Maturity onset diabetes mellitus in young

Uncertain:1

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

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 (rs755707550) in MODY yet. -

Hyperinsulinemic hypoglycemia, familial, 1

Uncertain:1

Jul 05, 2017

Counsyl

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Uncertain:1

Feb 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 657 of the ABCC8 protein (p.Arg657Gln). This variant is present in population databases (rs755707550, gnomAD 0.003%). This missense change has been observed in individual(s) with autosomal dominant congenital hyperinsulinism (PMID: 26431509). ClinVar contains an entry for this variant (Variation ID: 552764). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The glutamine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change affects ABCC8 function (PMID: 26431509). 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. -

Transitory neonatal diabetes mellitus

Uncertain:1

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: research

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.067

BayesDel_addAF

Benign

-0.048

BayesDel_noAF

Benign

-0.29

CADD

Benign

DANN

Uncertain

0.98

DEOGEN2

Benign

0.35

.;.;T;.;.;.;.;.

Eigen

Benign

-0.92

Eigen_PC

Benign

-0.87

FATHMM_MKL

Benign

0.14

LIST_S2

Benign

0.85

T;.;T;T;T;T;T;T

M_CAP

Uncertain

0.085

MetaRNN

Benign

0.088

T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.70

MutationAssessor

Benign

1.7

.;L;L;L;.;.;.;.

PrimateAI

Benign

0.21

PROVEAN

Benign

-0.39

.;.;N;N;.;.;.;.

REVEL

Benign

0.15

Sift

Benign

0.52

.;.;T;T;.;.;.;.

Sift4G

Benign

0.35

.;.;T;T;.;.;.;.

Polyphen

0.0060

.;.;B;.;.;.;.;.

Vest4

0.22, 0.21

MutPred

0.40

.;Loss of MoRF binding (P = 0.0188);Loss of MoRF binding (P = 0.0188);Loss of MoRF binding (P = 0.0188);.;.;.;.;

MVP

0.69

MPC

0.30

ClinPred

0.13

GERP RS

2.0

Varity_R

0.062

gMVP

0.23

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over