IGFBP2 and obesity due to melanocortin 4 receptor deficiency: ,19,20,21,22,23,24,25 A smaller, 220-kb distal deletion (BP2–3; chr16:28.82–29.04 Mb; GRCh37) has been associated with early-onset obesity, macrocephaly, ASD and schizophrenia,14,15,26,27 and increased rate of obesity and T2D in population-based cohorts.18