7-44152312-A-C

Position:

• chr7-44152312-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PP2 PP3 PM5 PM2_Supporting

This summary comes from the ClinGen Evidence Repository: The c.322T>G variant in the glucokinase gene,GCK, causes an amino acid change of tyrosine to aspartic acid at codon 108 (p.(Tyr108Asp)) of NM_000162.5. 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 0.967, which is greater than the MDEP VCEP threshold of 0.70 (PP3). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant has been reported as likely pathogenic in ClinVar; however, no clinical information was provided (ClinVar ID: 36212). Another missense variant, c.322T>C p.Tyr108His,has been interpreted as pathogenic by the ClinGen MDEP, and p.Tyr108Asp has a greater Grantham distance (PM5). In summary, c.322T>G 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 1.3.0, approved 8/11/2023): PM5, PP2, PP3, PM2_Supporting. LINK:https://erepo.genome.network/evrepo/ui/classification/CA213777/MONDO:0015967/086

• Frequency: Genomes: not found (cov: 33)
• Consequence: GCK NM_000162.5 missense
• Clinical Significance: Uncertain significance reviewed by expert panel P:1 U:1 O:1
• Conservation: PhyloP100: 9.31

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM5: 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GCK	NM_000162.5	c.322T>G	p.Tyr108Asp	missense_variant	3/10	ENST00000403799.8	NP_000153.1
GCK	NM_033507.3	c.325T>G	p.Tyr109Asp	missense_variant	3/10		NP_277042.1
GCK	NM_033508.3	c.319T>G	p.Tyr107Asp	missense_variant	4/11		NP_277043.1
GCK	NM_001354800.1	c.322T>G	p.Tyr108Asp	missense_variant	3/11		NP_001341729.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GCK	ENST00000403799.8	c.322T>G	p.Tyr108Asp	missense_variant	3/10	1	NM_000162.5	ENSP00000384247.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

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

Likely pathogenic, criteria provided, single submitter

clinical testing;curation

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

Aug 18, 2011

- -

Monogenic diabetes Uncertain:1

Uncertain significance, reviewed by expert panel

curation

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Jan 18, 2024

The c.322T>G variant in the glucokinase gene,GCK, causes an amino acid change of tyrosine to aspartic acid at codon 108 (p.(Tyr108Asp)) of NM_000162.5. 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 0.967, which is greater than the MDEP VCEP threshold of 0.70 (PP3). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant has been reported as likely pathogenic in ClinVar; however, no clinical information was provided (ClinVar ID: 36212). Another missense variant, c.322T>C p.Tyr108His,has been interpreted as pathogenic by the ClinGen MDEP, and p.Tyr108Asp has a greater Grantham distance (PM5). In summary, c.322T>G 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 1.3.0, approved 8/11/2023): PM5, PP2, PP3, PM2_Supporting. -

Maturity onset diabetes mellitus in young Other:1

Uncertain risk allele, criteria provided, single submitter

research

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

-

Potent mutations in GCK gene is associated with poor secretion of insulin. Its associated with milder forms of diabetes, which can be controlled by diet . However, there is no sufficient evidence to ascertain the significance of rs193922292 in MODY, yet. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	31
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.93	.;D;.;.;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.95	D;D;.;D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.1	.;M;.;.;.
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-8.9	.;D;D;D;D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	.;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	D;D;D;D;.
Vest4		0.91
MutPred		0.80		.;Gain of disorder (P = 0.0064);.;.;Gain of disorder (P = 0.0064);
MVP		0.99
MPC		2.7
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.97
gMVP		1.0

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: rs193922292; hg19: chr7-44191911;