Manhattan plot representing methylation in the 15q11.2-15q12 region in the twin pairs of Family 1. This region spans from SNRPN to UBE3A and encompasses members of the SNORD115 and SNORD116 gene families (top). A red dot indicates a decrease in methylation in the affected twin. A blue dot indicates an increase in methylation in the affected twin (Family 1). This region contains a complex regulatory ncRNA involved in imprinting control and neurodevelopment.