Clinical data prevalence in the studied series is resumed in Fig. 1: PTH resistance was detected in most patients with genetic mutations (n = 43/46, 93%) at a median age of 5 years (range 0.9–23.4), while all patients with imprinting alterations showed rPTH at diagnosis, often occurring later in life (median age 11.6 years; range 0.5– 65), with symptomatic hypocalcaemia. Here, PTH is linked to Hypocalcemia.