We then checked other pituitary hormones to rule out hypopituitarism, and the results showed normal follicle-stimulating hormone (FSH: 5.2 mIU/mL), normal luteinizing hormone (LH: 3.79 mIU/mL), low testosterone (testosterone: 1.98 ng/mL), normal to low prolactin (prolactin: 3.7 ng/mL), normal human growth hormone (0.07 ng/mL), and low insulin-like growth factor-1 (39.70 ng/mL) for his age. The gene discussed is PRL; the disease is hypopituitarism.