A genetic disorder that is characterized by decreased urinary calcium excretion and (usually asymptomatic) hypercalcemia. PTH levels are normal in most patients. Caused by an autosomal dominant mutation of a calcium-sensing receptor in the kidneys and parathyroid gland (CaSR gene).

• Clinical features
  • Usually asymptomatic
  • Neonatal hypocalcemia in children of mothers with FHH (e.g., paresthesias, muscle spasms, seizures)
• Diagnosis
  • Hypercalcemia and inappropriately normal or increased PTH
  • Hypocalciuria
• Therapy
  • No treatment necessary