FHH2 is characterized by hypercalcemia, inappropriately normal or raised parathyroid hormone (PTH) concentrations, and normal or low urinary calcium excretion.
FBH is characterized by symptomless hypercalcemia, low urinary calcium excretion, normal iPTH values, generally normal parathyroid histology, and failure of subtotal parathyroidectomy is normalize serum calcium.