GCK and diabetes mellitus: Genetic testing for monogenic diabetes with a custom Illumina Nextera rapid capture next-generation sequencing panel on an Illumina Miseq sequencing platform (HNF4A, GCK, HNF1A, PDX1, HNF1B, NEUROD1, KLF11, CEL, PAX4, INS, ABCC8, KCNJ11) was performed on members of the family who were recruited for the clinical study.