Copy number variations in "classical" obesity candidate genes are not frequently associated with severe early-onset obesity in children.
Windholz J, Kovacs P, Schlicke M, Franke C, Mahajan A, Morris AP, Lemke JR, Klammt J, Kiess W, Schöneberg T, et al. J Pediatr Endocrinol Metab. 2017 May 1; 30(5):507-515.