Previous studies involving adult patients with macroprolactinomas identified LH and FSH deficiency in 73–93% of patients, TSH deficiency in 41% of patients, and ACTH deficiency in 12–23% of patients at diagnosis (54, 56), whereas a recent study by Breil et al. (39) involving 12 pediatric patients with prolactinomas identified GH deficiency in 41.7% of patients, TSH deficiency in 33.3% of patients, LH and FSH deficiency in 25% of patients, and ACTH deficiency in 17% of patients. The gene discussed is PLOD1; the disease is central congenital hypothyroidism.