Genes involved in chromatin stabilization, remodeling, or editing—such as DNA mismatch repair genes (e.g., mutL homolog 1 [MLH1], mutS homolog 2 [MSH2], and mutS homolog 6 [MSH6]) and homologous repair deficiency (HRD) genes (e.g., breast cancer susceptibility—BRCA1/2 and the partner and localizer of BRCA2, PALB2)—also play significant roles and warrant further study. The gene discussed is MSH6; the disease is hyperinsulinemic hypoglycemia, familial, 4.