title: [Usefulness of genetic tests in familial hypocalciuric hypercalcemia with atypical clinical presentation].
abstract: OBJECTIVE
  Biochemical tests related to calcium and phosphorus metabolism have traditionally been considered as a reliable tool to differentiate familial hypocalciuric hypercalcemia (FHH) from primary hyperparathyroidism (PHPT). However, diagnosis may sometimes be difficult even for experienced clinicians. Our objective was to assess the accuracy of diagnostic tests in FHH and the circumstances in which genetic studies are required.
  
  
  METHODS
  A descriptive study was conducted of two families with hypercalcemia and suspected atypical FHH. Urinary calcium excretion was measured in 24-hour urine using different tests (calcium excretion (CE), urinary calcium/creatinine clearance ratio (UCCR)), and serum PTH and 25-hydroxyvitamin D levels were tested. Index cases underwent genetic study.
  
  
  RESULTS
  One patient from the first family showed overt, persistent hypercalciuria with values more consistent with PHPT than with FHH if we consider, as proposed by guidelines, a UCCR lower than 0.01 as diagnostic of FHH and a value higher than 0.02 as diagnostic of PHPT. The index case of the second family underwent surgery for a parathyroid adenoma. Both cases had a mutation c. 164C>T (Pro55Leu) in exon 2 in heterozygosis.
  
  
  CONCLUSIONS
  According to current clinical guidelines, definitive diagnosis of FHH requires genetic confirmation, which allowed in our case for detection of two families with FHH and atypical clinical presentations. We think that rational use of genetic tests may avoid unnecessary surgery and excess monitoring costs.
authors.affiliation: Unidad de Gestión Clínica, Endocrinología y Nutrición, Hospital Universitario Virgen de Valme, Sevilla, España. idomingof@ono.com
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández López
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández Peña
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Cózar León
authors.forename: María Mar
authors.initials: MM
authors.lastname: Viloria Peñas
authors.forename: Guillermo
authors.initials: G
authors.lastname: Martínez De Pinillos Gordillo
authors.forename: Mariana Tomé
authors.initials: MT
authors.lastname: Fernández-Ladreda
authors.forename: Santiago
authors.initials: S
authors.lastname: Duran García
mesh_terms: D000328:Adult; D005260:Female; D005820:Genetic Testing; D006801:Humans; D006934:Hypercalcemia / Q000151:congenital* / Q000175:diagnosis / Q000235:genetics; D008297:Male