chr7-44145614-G-T

Variant names:

• chr7-44145614-G-T
• rs193922265
• NM_000162.5:c.1136C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM3 PP2 PP3 PP4 PM2_Supporting PS4_Moderate

This summary comes from the ClinGen Evidence Repository: The c.1136C>A variant in the glucokinase gene, GCK, causes an amino acid change of alanine to proline at codon 379 (p.(Ala379Glu)) of NM_000162.5. GCK is defined by the ClinGen MDEP VCEP as a gene that has a low rate of benign missense variation and where pathogenic missense variants are a common mechanism of disease (PP2). This variant is predicted to be deleterious by computational evidence, with a REVEL score of 0.985, 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 was identified in five unrelated individuals with non-autoimmune/insulin-deficient diabetes (PS4_Moderate; PMID 30592380, internal lab contributors). This variant was identified in an individual with a clinical history highly specific for GCK-MODY (FBG 5.5-8 mmol/L and HbA1c 5.6 - 7.6%) (PP4; PMID:30592389) (PP4; internal lab contributors). This variant has been detected in one individual with neonatal diabetes. This individual was compound heterozygous for the variant and a pathogenic variant and was confirmed in trans by parental/family testing (PM3; PMID 30592380). Functional studies demonstrated the p.Ala379Glu protein has RAI<0.5; however, the wild-type kinetic parameters didn’t pass the quality control, and the PS3 cannot be applied (PMID:30592380). In summary, this variant meets the criteria to be classified as likely pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP VCEP (specification version 1.2.0, approved 6/7/2023): PP2, PP3, PM2_Supporting, PP4, PM3, PS4_Moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA213717/MONDO:0015967/086

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: GCK NM_033507.3 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:4
• Conservation: PhyloP100: 8.02
• Publications: 13 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.

• PS4: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: 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_033507.3. 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.1136C>A	p.Ala379Glu	missense	Exon 9 of 10	NP_000153.1
	GCK	NM_033507.3		c.1139C>A	p.Ala380Glu	missense	Exon 9 of 10	NP_277042.1
	GCK	NM_033508.3		c.1133C>A	p.Ala378Glu	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.1136C>A	p.Ala379Glu	missense	Exon 9 of 10	ENSP00000384247.3
	GCK	ENST00000395796.8	TSL:1	n.*1134C>A		non_coding_transcript_exon	Exon 10 of 11	ENSP00000379142.4
	GCK	ENST00000459642.1	TSL:1	n.516C>A		non_coding_transcript_exon	Exon 1 of 2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1454700 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 723700

African (AFR) AF: 0.00 AC: 0 AN: 33414

American (AMR) AF: 0.00 AC: 0 AN: 44336

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26032

East Asian (EAS) AF: 0.00 AC: 0 AN: 39568

South Asian (SAS) AF: 0.00 AC: 0 AN: 85678

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 48970

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110750

Other (OTH) AF: 0.00 AC: 0 AN: 60194

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
1	-	-	Maturity onset diabetes mellitus in young (1)
1	-	-	Maturity-onset diabetes of the young type 2 (1)
1	-	-	Monogenic diabetes (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.92	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Pathogenic	4.0	H
PhyloP100		8.0
PrimateAI	Pathogenic	0.80	D
PROVEAN	Pathogenic	-4.8	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		0.99	D
Vest4		0.84
MutPred		0.98		Gain of disorder (P = 0.0373)
MVP		0.99
MPC		2.4
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.99
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: rs193922265; hg19: chr7-44185213;