7-44153411-A-G

Variant names:

• chr7-44153411-A-G
• rs1554335954
• NM_000162.5:c.98T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PP2 PP3 PM2_Supporting PP4_Moderate PS4

This summary comes from the ClinGen Evidence Repository: The c.98T>C variant in the glucokinase gene, GCK, causes an amnio acid change of valine to alanine at codon 33 (p.(Val33Ala)) of NM_000162.5. This variant was identified in at least 17 unrelated individuals with hyperglycemia (PS4; PMID:22332836, 26641800, 36257325 internal lab contributors). This variant is absent from gnomAD v4.1.0 (PM2_Supporting). 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). This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.929, which is greater than the MDEP VCEP threshold of 0.70 (PP3). This variant was identified in an individual with a clinical history highly specific for GCK-hyperglycemia (fasting glucose 5.5-8 mmol/L and HbA1c 5.6 - 7.6% and antibody negative (PP4_Moderate; internal lab contributors). The relative activity index (RAI) of this variant was above the MDEP cutoff of 0.5, and thermostability was not evaluated; therefore PS3 was not applied (PMID:28842611). Additional missense variants at the same codon, c.98T>A p.(Val33Glu) and c.98T>G p.(Val33Gly) have been classified as a VUS by the ClinGen MDEP; therefore, PM5 will not be applied. In summary, c.98T>C meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 2.0.0, approved 2/17/2025): PS4, PM2_Supporting, PP2, PP3, PP4_Moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA367403604/MONDO:0015967/086

• Frequency: Genomes: not found (cov: 32)
• Consequence: GCK NM_000162.5 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:3 U:1
• Conservation: PhyloP100: 9.29
• Publications: 1 publications found

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 Gene-Disease associations (from GenCC):

• hyperinsulinism due to glucokinase deficiency

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• maturity-onset diabetes of the young type 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
• monogenic diabetes

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

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• permanent neonatal diabetes mellitus 1

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
• transient neonatal diabetes mellitus

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp
• maturity-onset diabetes of the young

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• permanent neonatal diabetes mellitus

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PP2: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: For more information check the summary or visit ClinGen Evidence Repository.
• PP4: 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	c.98T>C	p.Val33Ala	missense_variant	Exon 2 of 10	ENST00000403799.8	NP_000153.1
GCK	NM_033507.3	c.101T>C	p.Val34Ala	missense_variant	Exon 2 of 10		NP_277042.1
GCK	NM_033508.3	c.95T>C	p.Val32Ala	missense_variant	Exon 3 of 11		NP_277043.1
GCK	NM_001354800.1	c.98T>C	p.Val33Ala	missense_variant	Exon 2 of 11		NP_001341729.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCK	ENST00000403799.8	c.98T>C	p.Val33Ala	missense_variant	Exon 2 of 10	1	NM_000162.5	ENSP00000384247.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3 Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:1 Uncertain:1

Apr 30, 2018

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 01, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 33 of the GCK protein (p.Val33Ala). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with GCK-related conditions (PMID: 18271687, 20337973, 22332836). ClinVar contains an entry for this variant (Variation ID: 585930). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Maturity-onset diabetes of the young type 2 Pathogenic:1

Aug 02, 2022

Geisinger Clinic, Geisinger Health System

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

PM2, PP3, PS4_Moderate, PM5_Supporting, PP4, PP2 -

Monogenic diabetes Pathogenic:1

Jun 27, 2025

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The c.98T>C variant in the glucokinase gene, GCK, causes an amnio acid change of valine to alanine at codon 33 (p.(Val33Ala)) of NM_000162.5. This variant was identified in at least 17 unrelated individuals with hyperglycemia (PS4; PMID: 22332836, 26641800, 36257325 internal lab contributors). This variant is absent from gnomAD v4.1.0 (PM2_Supporting). 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). This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.929, which is greater than the MDEP VCEP threshold of 0.70 (PP3). This variant was identified in an individual with a clinical history highly specific for GCK-hyperglycemia (fasting glucose 5.5-8 mmol/L and HbA1c 5.6 - 7.6% and antibody negative (PP4_Moderate; internal lab contributors). The relative activity index (RAI) of this variant was above the MDEP cutoff of 0.5, and thermostability was not evaluated; therefore PS3 was not applied (PMID: 28842611). Additional missense variants at the same codon, c.98T>A p.(Val33Glu) and c.98T>G p.(Val33Gly) have been classified as a VUS by the ClinGen MDEP; therefore, PM5 will not be applied. In summary, c.98T>C meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 2.0.0, approved 2/17/2025): PS4, PM2_Supporting, PP2, PP3, PP4_Moderate. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.73
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	.;D;.;.;.
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.84	T;T;.;T;T
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.96	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.0	.;M;.;.;.
PhyloP100		9.3
PrimateAI	Uncertain	0.65	T
PROVEAN	Uncertain	-3.8	.;D;D;D;D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	.;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Polyphen		0.86	P;P;P;P;.
Vest4		0.75
MutPred		0.87		.;Loss of methylation at K32 (P = 0.0432);.;.;Loss of methylation at K32 (P = 0.0432);
MVP		1.0
MPC		2.3
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.85
gMVP		1.0
Mutation Taster		=1/99	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1554335954; hg19: chr7-44193010;