chr11-17427095-C-A

Variant names:

• chr11-17427095-C-A
• rs138687850
• NM_000352.6:c.2176G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000352.6(ABCC8):​c.2176G>T​(p.Ala726Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A726T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: ABCC8 NM_000352.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.11
• Publications: 10 publications found

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 Gene-Disease associations (from GenCC):

• hyperinsulinemic hypoglycemia, familial, 1

  Inheritance: AD, AR, SD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Illumina, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• diabetes mellitus, permanent neonatal 3

  Inheritance: AR, SD, AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
• familial hyperinsulinism

  Inheritance: AR Classification: DEFINITIVE Submitted by: Myriad Women’s Health
• diabetes mellitus

  Inheritance: SD Classification: DEFINITIVE Submitted by: Ambry Genetics
• monogenic diabetes

  Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen
• diabetes mellitus, noninsulin-dependent

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• hypoglycemia, leucine-induced

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• transient neonatal diabetes mellitus

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• permanent neonatal diabetes mellitus

  Inheritance: AR, AD Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• diabetes mellitus, transient neonatal, 2

  Inheritance: Unknown, AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• pulmonary arterial hypertension

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• autosomal dominant hyperinsulinism due to SUR1 deficiency

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• diazoxide-resistant focal hyperinsulinism due to SUR1 deficiency

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• maturity-onset diabetes of the young

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive hyperinsulinism due to SUR1 deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• type 2 diabetes mellitus

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 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_000352.6
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ABCC8	NM_000352.6	c.2176G>T	p.Ala726Ser	missense_variant	Exon 16 of 39	ENST00000389817.8	NP_000343.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ABCC8	ENST00000389817.8	c.2176G>T	p.Ala726Ser	missense_variant	Exon 16 of 39	1	NM_000352.6	ENSP00000374467.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

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

Mar 28, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Aug 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 726 of the ABCC8 protein (p.Ala726Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with ABCC8-related conditions. Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Uncertain	0.057	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	15
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.69	.;.;D;.;.;.;.;.
Eigen	Benign	-0.45
Eigen_PC	Benign	-0.35
FATHMM_MKL	Benign	0.69	D
LIST_S2	Uncertain	0.90	D;.;D;D;D;D;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Uncertain	0.55	D;D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.074	T
MutationAssessor	Benign	1.6	.;L;L;L;.;.;.;.
PhyloP100		2.1
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-0.66	.;.;N;N;.;.;.;.
REVEL	Benign	0.28
Sift	Benign	0.085	.;.;T;T;.;.;.;.
Sift4G	Uncertain	0.0060	.;.;D;D;.;.;.;.
Polyphen		0.014	.;.;B;.;.;.;.;.
Vest4		0.51, 0.50
MutPred		0.82		.;Gain of disorder (P = 0.0388);Gain of disorder (P = 0.0388);Gain of disorder (P = 0.0388);.;.;.;.;
MVP		0.84
MPC		0.26
ClinPred		0.54	D
GERP RS		2.9
Varity_R		0.24
gMVP		0.47
Mutation Taster		=86/14	polymorphism

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: rs138687850; hg19: chr11-17448642;