Primary hyperparathyroidism is a common endocrine disorder that is mostly caused by solitary tumors within the parathyroid glands. Characterized by early debut and higher frequency of multiple parathyroid masses, familial forms of primary hyperparathyroidism are caused by the already known mutations of: menin (MEN1 syndrome), RET proto-oncogene (MEN2 syndrome), HRPT2-parafibromin (hyperparathyroidism-jaw tumor syndrome), calcium sensing receptor gene (familial hypocalciuric hypercalcemia). A specific mutation in FIHP has not been identified in the majority of affected families. Recent studies revealed menin, HRPT2 and calcium-sensing receptor mutations in patients with FIHP. Whether FIHP is a variant or an early stage of MEN1 syndrome or hyperparathyroidism-jaw tumor syndrome is yet to be established. We present three siblings with familial isolated hyperparathyroidism due to solitary parathyroid adenoma and favorable evolution post-parathyroidectomy. Genetic tests revealed HRPT2 mutation.