The patient referred her mother since she was noted to have hypercalcemia based on further inquiry. Her mother, a 62-year-old Korean woman with a history of treated tuberculosis, hypertension, and hyperlipidemia had mild asymptomatic hypercalcemia. Her calcium levels from 1997 to 2014 ranged from 10.2 mg/dL to 11.3 mg/dL, and further testing revealed similar findings to her daughter (Table 1, mother). CT imaging of the chest and abdomen did not reveal kidney stones or evidence of sarcoidosis, and the neck US revealed a thyroid nodule found to be benign on FNA. Surgery was discouraged, and she agreed to genetic testing revealing a novel heterozygous variant in the calcium-sensing receptor gene (CaSR) resulting in a serine to leucine substitution at position 147 (S147L). After this, her daughter agreed to testing which revealed the same heterozygous variant in the CaSR.
On follow-up, the probands bony lesion was re-biopsied, 3 years after the initial biopsy and 1.5 years after surgery, revealing woven bone deposition and peritrabecular fibrosis, and it has been stable on imaging over 5.5 years. Repeat DXA (Hologic) 5.5 years after her initial one, and 3.5 years after parathyroid surgery, revealed increased bone density and Z scores of 0.798 (Z - 0.3), 0.927 (Z - 1.1), and 0.870 (Z - 0.5) in g/cm2 at the femoral neck, spine and hip, respectively, although the study was performed at a different location. Three years postoperatively, she continues to report a resolution in symptoms since her surgery, particularly in fatigue and mental clarity, yet remains hypoparathyroid (calcium 7.8 mg/dL; PTH 4 pg/mL) and on treatment with calcitriol and calcium. She had an uncomplicated pregnancy resulting in a healthy male child whose calcium so far has not been tested. Her mother remains asymptomatic.