NM_000162.5:c.478G>A

Variant names:

• chr7-44150961-C-T
• rs1554335566
• NM_000162.5:c.478G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5

The NM_000162.5(GCK):​c.478G>A​(p.Asp160Asn) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,638 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. D160H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: GCK NM_000162.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:3 U:1 O:1
• Conservation: PhyloP100: 4.98
• 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

ENSG00000300758 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 26 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 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 chr7-44150961-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1743101.
• 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 transient neonatal diabetes mellitus, monogenic diabetes, permanent neonatal diabetes mellitus 1, diabetes mellitus, noninsulin-dependent, maturity-onset diabetes of the young type 2, hyperinsulinism due to glucokinase deficiency, permanent neonatal diabetes mellitus, maturity-onset diabetes of the young.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.917
• PP5: Variant 7-44150961-C-T is Pathogenic according to our data. Variant chr7-44150961-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 447404.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCK	NM_000162.5	c.478G>A	p.Asp160Asn	missense_variant	Exon 4 of 10	ENST00000403799.8	NP_000153.1
GCK	NM_033507.3	c.481G>A	p.Asp161Asn	missense_variant	Exon 4 of 10		NP_277042.1
GCK	NM_033508.3	c.475G>A	p.Asp159Asn	missense_variant	Exon 5 of 11		NP_277043.1
GCK	NM_001354800.1	c.478G>A	p.Asp160Asn	missense_variant	Exon 4 of 11		NP_001341729.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCK	ENST00000403799.8	c.478G>A	p.Asp160Asn	missense_variant	Exon 4 of 10	1	NM_000162.5	ENSP00000384247.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461638 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727128

African (AFR) AF: 0.00 AC: 0 AN: 33436

American (AMR) AF: 0.00 AC: 0 AN: 44706

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111878

Other (OTH) AF: 0.00 AC: 0 AN: 60374

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:3 Uncertain:1 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:2

Sep 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with asparagine, which is neutral and polar, at codon 160 of the GCK protein (p.Asp160Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with maturity-onset diabetes of the young (PMID: 19790256, 25015100, 32533152, 33852230, 36257325; internal data). ClinVar contains an entry for this variant (Variation ID: 447404). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt GCK protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects GCK function (PMID: 25015100). This variant disrupts the p.Asp160 amino acid residue in GCK. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 29056535, 30608898). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Mar 26, 2018

Athena Diagnostics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Aug 02, 2022

Geisinger Clinic, Geisinger Health System

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

PM2, PP1_Strong, PS4, PM5_Supporting, PP4, PP2, PS3 -

not specified Uncertain:1

Jul 22, 2024

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: GCK c.478G>A (p.Asp160Asn) results in a conservative amino acid change located in the Hexokinase, N-terminal domain (IPR022672) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant was absent in 251458 control chromosomes (gnomAD). c.478G>A has been reported in the literature in individuals affected with maturity-onset diabetes of the young as well as in two carriers in non-diabetes (Osbak_2009, Raimondo_2014, Caswell_2020, Breidbart_2021, Mirshahi_2022, Billings_2022). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function (Raimondo_2014). The following publications have been ascertained in the context of this evaluation (PMID: 36208030, 33852230, 32533152, 36257325, 19790256, 25015100). ClinVar contains an entry for this variant (Variation ID: 447404). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Maturity onset diabetes mellitus in young Other:1

-

Clinical Genomics, Uppaluri K&H Personalized Medicine Clinic

Significance: Uncertain risk allele

Review Status: criteria provided, single submitter

Collection Method: research

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 rs1554335566 in MODY, yet. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	-0.080
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.87	.;D;.;.;.
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D;D;.;D;D
M_CAP	Uncertain	0.16	D
MetaRNN	Pathogenic	0.92	D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Benign	0.71	.;N;.;.;.
PhyloP100		5.0
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-4.6	.;D;D;D;D
REVEL	Pathogenic	0.71
Sift	Benign	0.034	.;D;D;D;D
Sift4G	Benign	0.12	T;T;T;T;T
Polyphen		1.0	D;D;D;B;.
Vest4		0.91
MutPred		0.83		.;Loss of stability (P = 0.0639);.;.;.;
MVP		0.94
MPC		2.0
ClinPred		0.99	D
GERP RS		5.2
Varity_R		0.66
gMVP		0.90
Mutation Taster		=3/97	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: rs1554335566; hg19: chr7-44190560; COSMIC: COSV60786479; COSMIC: COSV60786479;