MKRN3 and Prader-Willi syndrome: In this study, it was recognized that patients with larger 15q11.2 deletions, including most factors of the PWS critical region, had PWS phenotype without early pubertal development, whereas those with smaller deletions, including only MKRN3 or MKRN3 and additional few factors next to it, did not have PWS phenotype, but had early pubertal development.