Objective: We report two Hungarian patients with familial hypocalciuric hypercalcemia (FHH) caused by a mutation of the calcium-sensing receptor (CaSR) at codon 55. The proband and her father were heterozygous for this mutation.
Design: We performed detailed clinical and laboratory assessments of this family to characterize the effects of CaSR mutation on several endocrine organs expressing CaSR.
Results: Interestingly, we could not detect any failure in the function of any tissues we examined, except in serum calcium levels.
Conclusions: To our knowledge, this has been the first report from Eastern and Central Europe showing P55 L mutation of the CaSR, as well as the first publication discussing the effect of this mutation on several endocrine systems containing CASR.