Among our MEN1 PHPT patients was a male young adult (25 years) manifesting hypercalcemic PHPT from the age of 16 and a pituitary macroadenoma secreting high levels of prolactin from the age of 12, with a very severe osteoporosis at lumbar spine (T- and Z-scores both −4.4) and osteoporosis at total femur and femoral neck. The gene discussed is PRL; the disease is osteoporosis.