The patient presented here carries a novel de novo nonsense pathogenic variant of IGSF1 and has a clinical phenotype of above average birth weight, central hypothyroidism, delayed puberty, obesity, transient partial GH deficiency followed by high insulin-like growth factor-1 (IGF-1) concentration, macroorchidism, reduced attention, low DHEAS, and normoprolactinemia. The gene discussed is IGSF1; the disease is obesity due to melanocortin 4 receptor deficiency.