INS and endocrine system disorder: In the NIS database, the most prevalent REDs were rare disorders of calcium and phosphate homeostasis (0.90%), followed by genetic disorders of glucose and insulin homeostasis (0.54%), rare hypothalamic or pituitary disease (0.46%), rare thyroid disease (0.35%), rare adrenal disease (0.29%), genetic endocrine tumour syndromes (0.24%), rare sex development disorders and maturation disorders (0.12%), rare growth and genetic obesity syndromes (0.06%), and other rare endocrine diseases (0.03%).