BRCA1 and hyperinsulinemic hypoglycemia, familial, 4: In this study, nine of 138 patients had mutations in BRCA1/2, two patients were homologous recombination deficiency (HRD) positive (no mutation in BRCA1/2), 28 patients had no mutations in BRCA1/2, and 99 patients were not tested for BRCA1/2 mutation status.