Familial hypocalciuric hypercalcemia: new mutation in the CASR gene converting valine 697 to methionine.

[familial hypocalciuric hypercalcemia]

Familial hypocalciuric hypercalcemia is an uncommon cause of hypercalcemia that arises from mutations in the calcium-sensing receptor gene . Inactivation of this receptor leads to a decreased receptor sensitivity to calcium , determining that higher concentrations of calcium are needed to inhibit the release of parathormone in the parathyroid glands . Patients usually are asymptomatic . Diagnosis is usually made casually after a routine blood analysis . The syndrome is characterized by mild or moderate hypercalcemia , hypocalciuria , and normal or slightly increased levels of parathormone . The degree of hypercalcemia depends on the type of mutation . The accurate diagnosis is important since it is a benign disorder that does not require medical or surgical treatment . We report a 9 -year -old female with persistent hypercalcemia in several routine blood analyses , who was diagnosed with familial hypocalciuric hypercalcemia after genetic studies were performed . A new mutation determining a nucleotide change c .2089 G >A in the calcium-sensing receptor gene (exon 7 ) was detected . This mutation was also found in the patient 's mother and brother .