Description
The c.802G>A variant in the glucokinase gene, GCK, causes an amino acid change of glutamic acid to lysine at codon 268 (p.(Glu268Lys)) of NM_000162.5. This variant segregated with diabetes/hyperglycemia, with four informative meioses in two families (PP1_Strong; internal lab contributors). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). This variant was identified in eight unrelated individuals with hyperglycemia (PS4; internal lab contributors). This variant was identified in an individual with a clinical history highly specific for GCK-hyperglycemia (FBG 5.5-8 mmol/L and HbA1c 5.6 - 7.6% and negative antibodies) (PP4_Moderate; internal lab contributors). 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 0.727, which is greater than the MDEP VCEP threshold of 0.70 (PP3). In summary, c.802G>A meets the criteria to be classified as pathogenic for monogenic diabetes. ACMG/AMP criteria applied, as specified by the ClinGen MDEP (specification version 1.3.0, approved 8/11/2023): PP1_Strong, PS4, PP4_Moderate, PP2, PP3, PM2_Supporting.
# | Sample | Method | Observation |
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Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
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1 | germline | unknown | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |