11-17476632-T-C

Position:

• chr11-17476632-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP5

The NM_000352.6(ABCC8):​c.145A>G​(p.Ile49Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,586 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: ABCC8 NM_000352.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 7.74

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-17476632-T-C is Pathogenic according to our data. Variant chr11-17476632-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1691230.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
ABCC8	NM_000352.6	c.145A>G	p.Ile49Val	missense_variant	1/39	ENST00000389817.8	NP_000343.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
ABCC8	ENST00000389817.8	c.145A>G	p.Ile49Val	missense_variant	1/39	1	NM_000352.6	ENSP00000374467.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459586 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726118

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 29, 2022

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Ile49 amino acid residue in ABCC8. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 21109997, 26208381, 32893419). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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 ABCC8 protein function. ClinVar contains an entry for this variant (Variation ID: 1691230). This variant has not been reported in the literature in individuals affected with ABCC8-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 49 of the ABCC8 protein (p.Ile49Val). -

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 (rs1554949196) in MODY yet. -

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 (rs1554949196) in neonatal diabetes yet. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.38	.;.;T;.;.;.;.;.;.
Eigen	Uncertain	0.34
Eigen_PC	Uncertain	0.37
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.97	D;.;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Uncertain	0.54	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Uncertain	2.4	.;M;M;M;.;.;.;.;M
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-0.42	.;.;N;N;.;.;.;.;.
REVEL	Uncertain	0.58
Sift	Benign	0.43	.;.;T;T;.;.;.;.;.
Sift4G	Benign	0.10	.;.;T;T;.;.;.;.;D
Polyphen		0.59	.;.;P;.;.;.;.;.;.
Vest4		0.58, 0.59, 0.66
MutPred		0.36		Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);Loss of sheet (P = 0.0126);
MVP		0.94
MPC		0.57
ClinPred		0.95	D
GERP RS		4.5
Varity_R		0.15
gMVP		0.55

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: rs1554949196; hg19: chr11-17498179;