Although no data exist about sexual dimorphism on pro-UGN circulating levels in prepubertal children, supporting the present data, a recent work reported a sexual dimorphism in the circulating levels of the UGN precursor (pro-uroguanylin) in patients with obesity with higher levels in males with obesity when compared with females with obesity10. The gene discussed is GUCA2B; the disease is obesity due to melanocortin 4 receptor deficiency.