7-44149793-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PP2PP3

This summary comes from the ClinGen Evidence Repository: The c.646G>A variant in the glucokinase gene, GCK, causes an amino acid change of glutamic acid to lysine at codon 216 (p.Glu216Lys) of NM_000162.5. This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.711, which is greater than the MDEP VCEP threshold of 0.70 (PP3). Additionally, GCK is defined by the ClinGen MDEP as a gene that has a low rate of benign missense variation and has pathogenic missense variants as a common mechanism of disease (PP2). The Popmax filtering allele frequency of the c.646G>A variant in gnomAD v2.1.1 is 0.00001897 (East Asian), which falls between ClinGen MDEP-established cutoffs for PM2_Supporting (0.000003) and BS1 (0.00004); thus, neither criterion will be applied. In summary, c.646G>A meets the criteria to be classified as a variant of uncertain significance for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.2.0, approved 6/7/2023): PP3, PP2. LINK:https://erepo.genome.network/evrepo/ui/classification/CA4239565/MONDO:0015967/086

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

GCK
NM_000162.5 missense

Scores

Clinical Significance

Uncertain significance reviewed by expert panel U:5

Conservation

PhyloP100: 7.91

Variant links:

Genes affected

GCK (HGNC:4195): (glucokinase) This gene encodes a member of the hexokinase family of proteins. Hexokinases phosphorylate glucose to produce glucose-6-phosphate, the first step in most glucose metabolism pathways. In contrast to other forms of hexokinase, this enzyme is not inhibited by its product glucose-6-phosphate but remains active while glucose is abundant. The use of multiple promoters and alternative splicing of this gene result in distinct protein isoforms that exhibit tissue-specific expression in the pancreas and liver. In the pancreas, this enzyme plays a role in glucose-stimulated insulin secretion, while in the liver, this enzyme is important in glucose uptake and conversion to glycogen. Mutations in this gene that alter enzyme activity have been associated with multiple types of diabetes and hyperinsulinemic hypoglycemia. [provided by RefSeq, Aug 2017]

GCK links:

LOC105375258 (HGNC:):

LOC105375258 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PP2

For more information check the summary or visit ClinGen Evidence Repository.

PP3

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCK	NM_000162.5 link	c.646G>A	p.Glu216Lys	missense_variant	Exon 6 of 10	ENST00000403799.8	NP_000153.1	P35557-1Q53Y25

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCK	ENST00000403799.8 link	c.646G>A	p.Glu216Lys	missense_variant	Exon 6 of 10	1	NM_000162.5	ENSP00000384247.3		P35557-1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000278

AC:

AN:

251456

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135916

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000116

AC:

AN:

1461820

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727210

show subpopulations

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000126

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74324

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000901

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.0000330

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Mar 30, 2019

Athena Diagnostics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 216 of the GCK protein (p.Glu216Lys). This variant is present in population databases (rs778550411, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with GCK-related conditions. ClinVar contains an entry for this variant (Variation ID: 447412). 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 GCK protein function with a negative predictive value of 80%. 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. -

not specified

Uncertain:1

Dec 24, 2024

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: GCK c.646G>A (p.Glu216Lys) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2.8e-05 in 251456 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.646G>A in individuals affected with Monogenic Diabetes and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 447412). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Monogenic diabetes

Uncertain:1

Jul 30, 2023

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The c.646G>A variant in the glucokinase gene, GCK, causes an amino acid change of glutamic acid to lysine at codon 216 (p.Glu216Lys) of NM_000162.5. This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.711, which is greater than the MDEP VCEP threshold of 0.70 (PP3). Additionally, GCK is defined by the ClinGen MDEP as a gene that has a low rate of benign missense variation and has pathogenic missense variants as a common mechanism of disease (PP2). The Popmax filtering allele frequency of the c.646G>A variant in gnomAD v2.1.1 is 0.00001897 (East Asian), which falls between ClinGen MDEP-established cutoffs for PM2_Supporting (0.000003) and BS1 (0.00004); thus, neither criterion will be applied. In summary, c.646G>A meets the criteria to be classified as a variant of uncertain significance for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.2.0, approved 6/7/2023): PP3, PP2. -

Type 2 diabetes mellitus;C0342277:Maturity-onset diabetes of the young type 2;C1865290:Hyperinsulinism due to glucokinase deficiency;C5393570:Permanent neonatal diabetes mellitus 1

Uncertain:1

Mar 22, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Pathogenic

0.28

BayesDel_noAF

Pathogenic

0.39

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.74

.;D;.;.;.

Eigen

Uncertain

0.53

Eigen_PC

Uncertain

0.64

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.93

D;D;.;D;D

M_CAP

Uncertain

0.21

MetaRNN

Pathogenic

0.88

D;D;D;D;D

MetaSVM

Pathogenic

0.92

MutationAssessor

Benign

0.58

.;N;.;.;.

PrimateAI

Uncertain

0.73

PROVEAN

Uncertain

-2.7

.;D;D;D;N

REVEL

Pathogenic

0.71

Sift

Benign

0.47

.;T;T;T;T

Sift4G

Benign

0.55

T;T;T;T;T

Polyphen

1.0

D;D;D;P;.

Vest4

0.84

MutPred

0.61

.;Gain of methylation at E216 (P = 0.0232);.;.;.;

MVP

0.98

MPC

2.4

ClinPred

0.88

GERP RS

6.2

Varity_R

0.82

gMVP

0.99

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

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