Variants of the melanocortin-4 receptor (MC4R) gene are the most common cause of monogenic obesity. In this situation; while obesity cannot be controlled with diet and exercise, it was shown that Glucagon-like-peptide-1 receptor agonists (GLP- 1 RA) provide weight loss in short term. In this paper, we present our experience with Liraglutide treatment in an adolescent patient carrying MC4R gene variant. A female patient had admitted first at the age of 12.5 years with a complaint of progressive weight gain. She had a marked excess of appetite since infancy. In the physical examination of the pubertal female patient with a body mass index (BMI) of 36.1kg/m2 (3.48 SDS), there was no pathological finding except diffuse acanthosis nigricans. Laboratory examinations revealed only insulin resistance. Weight loss couldnt be achieved with lifestyle changes, metformin and orlistat treatments In genetic examination, a sporadic heterozygous c.206T>G(p.I69R)
variant (reported previously) was found in the MC4R gene. GLP-1 RA Liraglutide treatment was initiated and a loss of 19.2% reduction was achieved in the patient's body weight and BMI at the end of 32 weeks. However, the patient, whose treatment compliance was disrupted due to significant gastrointestinal complaints, returned to her former weight within a few months after treatment was stopped. In our case carrying a pathogenic variant in the MC4R gene, decrease of appetite and weight loss were achieved with Liraglutide treatment, but this situation could not be maintained. In such cases, there is a need for effective and tolerable treatment options.