7-44145590-G-T

Variant names:

• chr7-44145590-G-T
• rs193921338
• NM_000162.5:c.1160C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PP2 PP3 PP4 PM2_Supporting PM5_Strong

This summary comes from the ClinGen Evidence Repository: The c.1160C>A variant in the glucokinase gene, GCK, causes an amino acid change of alanine to glutamic acid at codon 387 (p. (Ala387Glu)) of NM_000162.5. This variant has an incomputable gnomAD v2.1.1 Grpmax filtering allele frequency due to one copy in the European non-Finnish subpopulation and no copies in any other subpopulation, thereby meeting the ClinGen MDEP threshold criteria for PM2_Supporting (ENF Popmax FAF <= 0.000003 and <= 2 copies in ENF and <=1 copy in any other subpopulation) (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 located in the larger hexokinase domain of the GCK gene (PMID:31638168) but this variant does not reside in an amino acid that directly binds glucose or ATP, which is defined as critical for the protein’s function by the ClinGen MDEP, so it does not meet PM1. This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.958 which is greater than the MDEP VCEP threshold of 0.70 (PP3). Two other missense variants, c.1159G>A p.(Ala387Thr) and c.1160C>T p.(Ala387Val) have been interpreted as pathogenic by the ClinGen MDEP (PM5_Strong). This variant was identified in an individual with a clinical history highly specific for GCK-hyperglycemia (FBG 5.5-8 mmol/L and HbA1c 5.6 - 7.6%) (PP4; internal lab contributors). In summary, c.1160C>A meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP VCEP (VCEP specifications version v1.3.0; approved 8/11/2023): PP2, PP3, PM2_Supporting, PP4, PM5_Strong. LINK:https://erepo.genome.network/evrepo/ui/classification/CA213725/MONDO:0015967/086

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: GCK NM_000162.5 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: 9.90
• Publications: 14 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

ENSG00000300758 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 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.
• PP4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000162.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCK	NM_000162.5	MANE Select	c.1160C>A	p.Ala387Glu	missense	Exon 9 of 10	NP_000153.1
	GCK	NM_033507.3		c.1163C>A	p.Ala388Glu	missense	Exon 9 of 10	NP_277042.1
	GCK	NM_033508.3		c.1157C>A	p.Ala386Glu	missense	Exon 10 of 11	NP_277043.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCK	ENST00000403799.8	TSL:1 MANE Select	c.1160C>A	p.Ala387Glu	missense	Exon 9 of 10	ENSP00000384247.3
	GCK	ENST00000395796.8	TSL:1	n.*1158C>A		non_coding_transcript_exon	Exon 10 of 11	ENSP00000379142.4
	GCK	ENST00000459642.1	TSL:1	n.540C>A		non_coding_transcript_exon	Exon 1 of 2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000436 AC: 1 AN: 229466 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000300

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.89e-7 AC: 1 AN: 1452264 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 722294

African (AFR) AF: 0.00 AC: 0 AN: 33342

American (AMR) AF: 0.0000227 AC: 1 AN: 44010

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25978

East Asian (EAS) AF: 0.00 AC: 0 AN: 39382

South Asian (SAS) AF: 0.00 AC: 0 AN: 85358

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49152

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1109296

Other (OTH) AF: 0.00 AC: 0 AN: 60008

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

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

Aug 18, 2011

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing;curation

Monogenic diabetes Pathogenic:1

Feb 28, 2024

ClinGen Monogenic Diabetes Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The c.1160C>A variant in the glucokinase gene, GCK, causes an amino acid change of alanine to glutamic acid at codon 387 (p. (Ala387Glu)) of NM_000162.5. This variant has an incomputable gnomAD v2.1.1 Grpmax filtering allele frequency due to one copy in the European non-Finnish subpopulation and no copies in any other subpopulation, thereby meeting the ClinGen MDEP threshold criteria for PM2_Supporting (ENF Popmax FAF <= 0.000003 and <= 2 copies in ENF and <=1 copy in any other subpopulation) (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 located in the larger hexokinase domain of the GCK gene (PMID: 31638168) but this variant does not reside in an amino acid that directly binds glucose or ATP, which is defined as critical for the protein's function by the ClinGen MDEP, so it does not meet PM1. This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.958 which is greater than the MDEP VCEP threshold of 0.70 (PP3). Two other missense variants, c.1159G>A p.(Ala387Thr) and c.1160C>T p.(Ala387Val) have been interpreted as pathogenic by the ClinGen MDEP (PM5_Strong). This variant was identified in an individual with a clinical history highly specific for GCK-hyperglycemia (FBG 5.5-8 mmol/L and HbA1c 5.6 - 7.6%) (PP4; internal lab contributors). In summary, c.1160C>A meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP VCEP (VCEP specifications version v1.3.0; approved 8/11/2023): PP2, PP3, PM2_Supporting, PP4, PM5_Strong.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		9.9
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-4.7	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.94		Gain of disorder (P = 0.0374)
MVP		0.99
MPC		2.3
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.98
gMVP		1.0
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs193921338; hg19: chr7-44185189;