Genetic deletion in PWS involves either the shorter paternal deletion (Type II) of 15q11-q13 or a larger, paternal Type I deletion that also includes the same 15q11.2 MDS region comprising TUBGCP5, NIPA1, NIPA2, and CYFIP1 (Bittel et al. 2006; Butler et al. 2004). The gene discussed is CYFIP1; the disease is Prader-Willi syndrome.