Laboratory examinations revealed significantly increased serum concentrations of GH (10.97 ng/mL, minimum value after 75 g glucose oral test) and PRL (585 ng/mL, normal range 4.6–21.4 ng/mL), mild hypercalcemia (10.7 mg/dL, normal range 8.5–10.1 mg/dL), hyperphosphatemia (5.48 mg/dL, normal range 2.6–4.6 mg/dL), slightly low PTH concentration (24 pg/mL, normal range 14.5–62.7 pg/mL), and increased bone turnover markers (c-terminal telopeptide [CTX] 1.99 ng/mL, normal range 0.299–0.573 ng/mL; bone alkaline phosphatase [B-ALP] 23.9 ug/L, normal range 11.4–24.6 ug/L). Here, GH1 is linked to hyperphosphatemia.