INS and obesity due to melanocortin 4 receptor deficiency: In previous studies, a 593‐kb deletion at map position B29.5–B30.1 Mb in the proximal region of 16p11.2 was defined as a typical 16p11.2 deletion commonly associated with symptoms of brain developmental abnormalities, while a 220‐kb deletion at map position B28.74–B28.95 Mb in the distal region was defined as an atypical 16p11.2 deletion featured by severe obesity due to the involvement of the SH2B1 gene, which plays a role in leptin and insulin signaling.