Schematic representation of the region 15q11.2-q13. The Prader-Willi syndrome (PWS) region is shown in violet, and Angelman syndrome (AS) region is shown in green. The red arrows indicate the three deletion breakpoints common to PWS and AS (BP1, BP2, and BP3). On rare occasions, there will be a distal breakpoint at BP4 or BP5. Type-1 deletions (T1D) extend from BP1 to BP3, and type-2 deletions (T2D) extend from BP2 to BP3.
