7-44149772-C-T

Variant names:

• chr7-44149772-C-T
• rs1360415315
• NM_000162.5:c.667G>A

Variant summary

Our verdict is Pathogenic. The variant received 23 ACMG points: 23P and 0B. PS3 PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000162.5(GCK):​c.667G>A​(p.Gly223Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,720 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV000613448: Studies show this variant reduces glucokinase activity (PMID:22291974, 22493702)." and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G223R) has been classified as Likely pathogenic. The gene GCK is included in the ClinGen Criteria Specification Registry.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GCK NM_000162.5 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:10
• Conservation: PhyloP100: 7.91
• Publications: 17 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: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• 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

LOC105375258 (HGNC:):

ACMG classification

Specifications for GCK are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Pathogenic. The variant received 23 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV000613448: Studies show this variant reduces glucokinase activity (PMID: 22291974, 22493702).; SCV002245936: Experimental studies have shown that this missense change affects GCK function (PMID: 22291974, 22493702).; SCV002559475: Published functional studies demonstrate kinetic inactivation with a decreased rate of catalysis and reduced affinity for glucose (Garca-Herrero et al., 2012; Valentnov et al., 2012); SCV002663328: In addition, a GST fusion protein with this alteration expressed in E. coli demonstrated activity levels <10% of wild type with altered kinetics (Garc&iacute;a-Herrero CM et al. PLoS ONE, 2012 Jan;7:e30518).; SCV004847449: In vitro functional studies, computational prediction tools, and conservation analyses support that this variant may impact the protein (Valentinova 2012 PMID 22493702).; SCV004122238: "At least one publication reports experimental evidence evaluating an impact on protein function and variant effect results in <10% of normal activity (Garcia-Herrero_2012)."; SCV005362520: This variant has been reported to be causative for maturity onset diabetes of the young (MODY) due to impaired kinetic characteristics of glucokinase (Borowiec et al. 2011. PubMed ID: 21437567; García-Herrero et al. 2012. PubMed ID: 22291974).
• PM1: In a hotspot region, there are 19 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 10 uncertain in NM_000162.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-44149772-C-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 2578075.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 274 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. Gene score misZ: 3.069 (below the threshold of 3.09). Trascript score misZ: 2.7821 (below the threshold of 3.09). GenCC associations: The gene is linked to monogenic diabetes, maturity-onset diabetes of the young type 2, hyperinsulinism due to glucokinase deficiency, permanent neonatal diabetes mellitus 1, diabetes mellitus, noninsulin-dependent, transient neonatal diabetes mellitus, permanent neonatal diabetes mellitus, maturity-onset diabetes of the young.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant 7-44149772-C-T is Pathogenic according to our data. Variant chr7-44149772-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 435306.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCK	NM_000162.5	MANE Select	c.667G>A	p.Gly223Ser	missense	Exon 6 of 10	NP_000153.1	Q53Y25
	GCK	NM_033507.3		c.670G>A	p.Gly224Ser	missense	Exon 6 of 10	NP_277042.1	P35557-2
	GCK	NM_033508.3		c.664G>A	p.Gly222Ser	missense	Exon 7 of 11	NP_277043.1	P35557-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCK	ENST00000403799.8	TSL:1 MANE Select	c.667G>A	p.Gly223Ser	missense	Exon 6 of 10	ENSP00000384247.3	P35557-1
	GCK	ENST00000395796.8	TSL:1	n.*665G>A		non_coding_transcript_exon	Exon 7 of 11	ENSP00000379142.4	A0A8C8KJG0
	GCK	ENST00000395796.8	TSL:1	n.*665G>A		3_prime_UTR	Exon 7 of 11	ENSP00000379142.4	A0A8C8KJG0

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461720 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727162

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86240

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53362

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111930

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	not provided (4)
2	-	-	Maturity-onset diabetes of the young (2)
1	-	-	GCK-related disorder (1)
1	-	-	Maturity-onset diabetes of the young type 2 (1)
1	-	-	Monogenic diabetes (1)
1	-	-	Type 2 diabetes mellitus;C0342277:Maturity-onset diabetes of the young type 2;C1833104:Permanent neonatal diabetes mellitus;C1865290:Hyperinsulinism due to glucokinase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	34
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.92	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.41	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.2	M
PhyloP100		7.9
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.9	D
REVEL	Pathogenic	0.94
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.94
MutPred		0.97		Gain of catalytic residue at G223 (P = 0.1571)
MVP		0.97
MPC		2.2
ClinPred		1.0	D
GERP RS		6.2
Varity_R		0.95
gMVP		1.0
Mutation Taster		=1/99	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.50		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.50		Position offset: 4

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1360415315; hg19: chr7-44189371;