Progression of PTH-resistance in autosomal dominant pseudohypoparathyroidism type Ib due to maternal STX16 deletions.

Establishing whether a STX16 deletion is inherited from a female carrier of a disease-causing variant rapidly establishes the diagnosis of AD-PHP1B. Several years before overt hypocalcemia developed, PTH levels increased thereby establishing the onset of PTH-resistance. Our findings provide diagnostic guidance and when treatment with calcium and calcitriol should be considered, in order to prevent hypocalcemia and associated sequelae.