PTH and Hypercalciuria: The detection of low phosphate levels in the presence of hyperparathyroidism is consistent with the phosphaturic action of PTH at kidney level; the concomitant tendency to higher calcium levels and higher renal calcium excretion were suggestive of a certain degree of inappropriate PTH secretion, identifying a condition distinct from that detected in cluster 2A patients, were increased PTH levels were likely secondary to hypercalciuria.