PTH and pseudohypoparathyroidism type 1A: Mutations in the gene encoding for G-protein (GNAS1) have been reported as cause of a more generalized form of hormone resistance [defined as pseudo-hypoparathyroidism type 1a (PHP1a)] with expression not only in thyroid but also in target tissues of the other involved hormones [kidney for parathyroid hormone (PTH), gonads for FSH/LH and pituitary for GHRH] (54).