The finding of persistent hypercalcemia suggests doing other medical tests to find the cause. Familial hypocalciuric hypercalcemia is usually benign and it requires no treatment. It is important to do CASR gene sequencing to avoid unnecessary treatments. We report a 12-year-old child, asymptomatic, with calcemia between 11.4 and 12.2 mg/dl. His father and two brothers presented asymptomatic hypercalcemia. The blood test with magnesium, phosphorus, 25 (OH) Vit D was normal, remarkable normal parathyroid hormone for the level of hypercalcemia. Urinary calcium/creatinine ratio was 0, 11 mg/dl and 24-hour urinary calcium was 1, 8 mg/kg per day. Abdominal and parathyroid ecography, long bone radiographs and densitometry were normal. Genetic study showed a mutation, c. 1651A> G, in exon 6 of the calciumsensing receptor gene, confirmed in father and brothers, too.