Autoimmune diseases that cause low parathyroid levels?

Hypercalcemia!: A low PTH means hypercalcemia! there are many diagnoses! see either a endocrine or rheumatology specialist!

Autoimmune hypopara: Autoimmune hypoparathyroidism is a very rare entity which causes low calcium and high phosphorus. It can be seen in autoimmune polyglandular syndrome type 1 (as part of a triad including mucocutaneous candidiasis and adrenal insufficiency) or by itself. This form of hypoparathyroidism can be very difficult to treat because it can also be complicated by vitamin d resistance.