A 7‑year‑old boy with Down syndrome developed early puberty and was treated with the peptide drug triptorelin, first as a monthly injection (3.75 mg) and later as a three‑monthly injection (11.25 mg). After three years his testicles got smaller, hormone levels dropped, and he had no reported side effects, suggesting the treatment worked well for his condition.

Gonadal dysfunction is a well-known endocrine manifestation of Down syndrome (DS) in men. Herein, we report a case of a seven-year-old boy with DS who developed precocious puberty, presenting with a six-month history of frequent erections, sudden growth spurts, and adult odors. Clinical examination revealed stage 2 puberty, with pubic hair development at stage 2 based on Tanner staging and bilateral testicular volumes of 6 mm. Laboratory tests indicated elevated luteinizing hormone (LH) and follicle-stimulating hormone levels and advanced bone age. A pituitary MRI revealed normal pituitary morphology without any detectable masses. The patient was initially prescribed monthly triptorelin acetate (Decapeptyl) intramuscular injections at a dose of 3.75 mg. Following six months, the treatment was switched to triptorelin pamoate (Diphereline) at a dose of 11.25 mg administered intramuscularly every three months. At age 10, following a three-year course of gonadotropin-releasing hormone (GnRH) agonist therapy, the patient demonstrated a notable decrease in testicular size and a reduction in LH levels, with no reported side effects. Conclusively, our findings imply that idiopathic central precocious puberty in boys with DS can be effectively managed with triptorelin pamoate injections, and early intervention may help alleviate the psychosocial impact of this condition.