The most prevalent are prolactin-secreting adenomas (50–60%), non-functioning pituitary adenomas (20–40%), growth hormone-secreting adenomas (10–15%) and adrenocorticotropin-secreting adenomas (5–8%) (Molitch 2017, Daly & Beckers 2020, Melmed 2020, Ho et al. 2021). The gene discussed is GH1; the disease is adenoma.