Submissions for variant NM_000162.5(GCK):c.629T>C (p.Met210Thr)

dbSNP: rs80356654

Total submissions: 5

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
ClinGen Monogenic Diabetes Variant Curation Expert Panel	RCV003493767	SCV004242367	pathogenic	Monogenic diabetes	2024-01-18	reviewed by expert panel	curation	The c.629T>C variant in the glucokinase gene, GCK, causes an amino acid change of methionine to threonine at codon 210 (p.(Met210Thr)) 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 0.982, which is greater than the MDEP threshold of 0.70 (PP3). A kinetic analysis of recombinant wild-type (WT) and mutant glucokinase demonstrated that the wild-type kinetic parameters pass the quality control, but the wild-type ATP Km is not between 0.4-0.65, and the p.Met210Thr has Kcat/S0.5<0.5 (PS3_Supporting; PMID: 14517946, DOI:10.1007/s001250051289). This variant has an incomputable gnomAD v2.1.1 Popmax filtering allele frequency of due to 0 copies observed in the European non-Finnish population and only 1 copy in another subpopulation (Latino/admixed), thereby meeting the ClinGen MDEP criteria for PM2_Supporting (PM2_Supporting). This variant was identified in 11 unrelated individuals with non-autoimmune and non-absolute/near-absolute insulin-deficient diabetes (PS4; PMIDs: 25555642, 9049484, ClinVar ID: 804852, internal lab contributor). This variant was identified in an individual with a phenotype suggestive of GCK-hyperglycemia; however, PP4 is unable to be evaluated due to insufficient clinical information (internal lab contributor). This variant segregated with diabetes, with 5 informative meioses in 2 families with MODY (PP1_Strong; internal lab contributors). Taken together, the evidence supports the classification of c.629T>C as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.2.0, approved 6/7/2023): PP1_Strong, PS4, PS3_Moderate, PP2, PP3, PM2_Supporting.
Athena Diagnostics	RCV000992058	SCV001144027	uncertain significance	not provided	2018-09-21	criteria provided, single submitter	clinical testing
Genetic Services Laboratory, University of Chicago	RCV000992058	SCV002069117	pathogenic	not provided	2018-03-09	criteria provided, single submitter	clinical testing
Women's Health and Genetics/Laboratory Corporation of America, LabCorp	RCV003117664	SCV003800667	likely pathogenic	Maturity-onset diabetes of the young type 2	2023-01-07	criteria provided, single submitter	clinical testing	Variant summary: GCK c.629T>C (p.Met210Thr) results in a non-conservative amino acid change located in the Hexokinase, N-terminal domain (IPR022672) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251462 control chromosomes. c.629T>C has been reported in the literature in individuals affected with Maturity Onset Diabetes Of The Young 2 (example, Velho_1997, Bennett_2015, Lizarzaburu-Robles_2020, Saint-Martin_2021). These data indicate that the variant is likely to be associated with disease. At-least one study reports experimental evidence demonstrating an impact on Glucokinase kinetic parameters, namely increased Km for ATP binding and decreased Kcat (approximately 12% of WT) for Glucokinase (Davies_1999). Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as pathogenic and one laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as likely pathogenic.
GeneDx	RCV000992058	SCV005201998	pathogenic	not provided	2024-02-29	criteria provided, single submitter	clinical testing	Published functional studies demonstrate that this variant causes significantly reduced enzyme activity (PMID: 10525657); Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are a common cause of disease and they are underrepresented in the general population; This variant is associated with the following publications: (PMID: 10525657, 18399931, 27913849, 14517946, 25555642, 9049484)