Additionally, a 2018 study found women with extreme obesity carrying the MC4R rs17782313 polymorphism tend to have higher BMIs before surgery, are less likely to achieve a non-obese BMI (<30 kg/m2), and typically maintain a BMI > 35 kg/m2, indicative of treatment failure [173]. This evidence concerns the gene MC4R and obesity due to melanocortin 4 receptor deficiency.