Familial hypocalciuric hypercalcaemia (FHH) is an autosomal dominant condition characterized by lifelong mild-to-moderate elevations of serum calcium concentrations in association with normal or mildly raised serum parathyroid hormone (PTH) concentrations and low urinary calcium excretion (1,2). The gene discussed is PTH; the disease is familial hypocalciuric hypercalcemia.