title: [Chronic hypocalcemia due to anti-calcium sensing receptor antibodies].
abstract: BACKGROUND
  Hypoparathyroidism is an entity associated with hypocalcemia, more frequently a consequence of neck surgery. An autoimmune etiology is rare and its diagnosis difficult to establish.
  
  
  METHODS
  52 year-old woman, with irrelevant past medical history and no significant familial conditions, referred because of hypocalcemia and basal ganglia calcifications, detected in the course of investigation of myalgias. Besides hypocalcemia (4.6 mg/ dL), hyperphosphatemia (8.7 mg/dL), undetectable parathyroid hormone and low urinary calcium, phosphorus and magnesium were present. Molecular analysis of CaSR gene excluded germinal mutations. Anti-calcium sensing receptor antibodies (anti-CaSR) were present. The patient is asymptomatic and normocalcemic under treatment with calcium and vitamin D.
  
  
  CONCLUSIONS
  Although rare, hypocalcemia due to anti-CaSR hypoparathyroidism must be considered in the absence of previous neck surgery, hypocalcemic drugs, familial history or phenotype suggesting a genetic disorder. Low or undetectable parathyroid hormone excludes pseudohypoparathyroidism and anti-CaSR positivity establishes the diagnosis.
authors.affiliation: Serviço de Endocrinologia. Instituto Português de Oncologia de Lisboa Francisco Gentil. Lisboa. Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Marques
authors.affiliation: Serviço de Endocrinologia. Instituto Português de Oncologia de Lisboa Francisco Gentil. Lisboa. Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Santos
authors.affiliation: Unidade de Investigação em Patobiologia Molecular. Instituto Português de Oncologia de Lisboa Francisco Gentil. Lisboa. Portugal.
authors.forename: Branca
authors.initials: B
authors.lastname: Cavaco
authors.affiliation: Serviço de Endocrinologia. Instituto Português de Oncologia de Lisboa Francisco Gentil. Lisboa. Portugal. Unidade de Investigação em Patobiologia Molecular. Instituto Português de Oncologia de Lisboa Francisco Gentil. Lisboa. Portugal. Centro de Estudos de Doenças Crónicas. Faculdade de Ciências Médicas. Universidade Nova de Lisboa. Lisboa. Portugal.
authors.forename: Valeriano
authors.initials: V
authors.lastname: Leite
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000276:immunology*; D008875:Middle Aged; D044169:Receptors, Calcium-Sensing / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D044169:Receptors, Calcium-Sensing