A 42-year-old female presents to the clinic with complaints of vague abdomi-
nal discomfort, weakness and fatigue, and bone pain. The patient gives no per-
sonal or family history of medical problems. The patient did remember that
she suffer from frequent urinary tract infections and has had several episodes
of kidney stones. Her physical examination was within normal limits. The
patient had a normal complete blood count (CBC), and electrolytes revealed a
significantly elevated calcium level and low phosphorus level.
What is the most likely diagnosis?
What is the biochemical secondary messenger activated
in this disorder?