Lucchesi et al. described one such kindred where dual variants were found in GCK and HNF1A, with the GCK variant ultimately classified as pathogenic and the HNF1A classified as a VUS through ClinGen Monogenic Diabetes Expert Panel guidance in conjunction with the family’s phenotype compatible with GCK-hyperglycaemia [11]. Here, HNF1A is linked to diabetes mellitus.