[Familial hypocalciuric hypercalcemia: a new mutation].

[familial hypocalciuric hypercalcemia]

Familial hypocalciuric hypercalcemia (FHH ) is a cause of hypercalcemia with autosomal dominant pattern of inheritance and high penetrance . In most of the cases it can be shown to be due to an inactivating mutation on the gene coding for the calcium-sensing receptor (CaSR ). Heterozygous cases usually do not present symptoms and they are diagnosed as an incidental finding . We report three affected children with an inactivating heterozygous mutation , p .Phe 789 del , in exon 7 of the calcium-sensing receptor gene (CASR gene ), situated in chromosome 3 q 21 (Ensembl ENSG 00000036828 ), which results in elevated serum calcium , normal o high level of parathyroid hormone (PTH ) and reduced urinary excretion with hypocalciuria . It is very important to determine the difference between FHH and primary hyperparathyroidism . Therefore , in a mild to moderate PTH -dependent hypercalcemia we must perform a family study and determine the urinary excretion of calcium . The presence of any other affected family member or reduced urinary calcium excretion is enough to suspect FHH , and this should be confirmed by the mutational analysis of the CASR gene , in order to establish the correct diagnosis , differentiated from primary hyperparathyroidism , to avoid unnecessary investigations or operations .

Diseases
Validation

Diseases presenting "calcium excretion" symptom

adrenal incidentaloma

aromatase deficiency

familial hypocalciuric hypercalcemia

kabuki syndrome

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