rs769268803
Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong
The NM_000162.5(GCK):c.766G>C(p.Glu256Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E256D) has been classified as Likely pathogenic.
Frequency
Consequence
NM_000162.5 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 18 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
GCK | NM_000162.5 | c.766G>C | p.Glu256Gln | missense_variant | 7/10 | ENST00000403799.8 | |
LOC105375258 | XR_927223.3 | n.97C>G | splice_region_variant, non_coding_transcript_exon_variant | 1/3 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
GCK | ENST00000403799.8 | c.766G>C | p.Glu256Gln | missense_variant | 7/10 | 1 | NM_000162.5 | P1 |
Frequencies
GnomAD3 genomes ? Cov.: 33
GnomAD4 exome Cov.: 32
GnomAD4 genome ? Cov.: 33
ClinVar
Submissions by phenotype
not provided Pathogenic:2
Likely pathogenic, criteria provided, single submitter | clinical testing | ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories | Jun 12, 2023 | The GCK c.766G>C; p.Glu256Gln variant (rs769268803), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 421063). This variant is also absent from the Genome Aggregation Database, indicating it is not a common polymorphism. The Glu256 residue is part of the glucose binding domain and is critical for GCK protein activity (Kamata 2004). Additionally, other amino acid substitutions at this codon (Ala, Asp, Gly, Lys) have been reported in individuals with MODY and are considered pathogenic (Campos Franco 2022, Garin 2008, Xu 2020, Zmyslowska 2022). Computational analyses predict that this variant is deleterious (REVEL: 0.951). Based on available information, this variant is considered to be likely pathogenic. References: Campos Franco P et al. Clinical and genetic characterization and long-term evaluation of individuals with maturity-onset diabetes of the young (MODY): The journey towards appropriate treatment. Diabetes Res Clin Pract. 2022 May;187:109875. PMID: 35472491. Garin I et al. Haploinsufficiency at GCK gene is not a frequent event in MODY2 patients. Clin Endocrinol (Oxf). 2008 Jun;68(6):873-8. PMID: 18248649. Kamata K et al. Structural basis for allosteric regulation of the monomeric allosteric enzyme human glucokinase. Structure. 2004 Mar;12(3):429-38. PMID: 15016359. Xu A et al. Molecular diagnosis of maturity-onset diabetes of the young in a cohort of Chinese children. Pediatr Diabetes. 2020 May;21(3):431-440. PMID: 31957151. Zmyslowska A et al. Next- generation sequencing is an effective method for diagnosing patients with different forms of monogenic diabetes. Diabetes Res Clin Pract. 2022 Jan;183:109154. PMID: 34826540. - |
Likely pathogenic, criteria provided, single submitter | clinical testing | GeneDx | May 09, 2016 | The E256Q variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. E256Q is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. The residue E256 is part of a glucose binding site and is crucial for GCK protein activity (Kamata et al., 2004). Missense variants in the same codon (E256K/D) and in nearby residues (V253L/F/A, N254H, Thr255A/S/I, W257R, G258R/S/C/D, A259T/V) have been reported in the Human Gene Mutation Database in association with diabetes (Stenson et al., 2014), supporting the functional importance of this region of the protein. Therefore, this variant is a strong candidate for a pathogenic variant, however the possibility it may be a rare benign variant cannot be excluded. - |
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at