CYFIP1 and Prader-Willi syndrome: This dissociation is also evident in patients with PWS who show an increase in OC behaviors that is unrelated to food and is exacerbated in Type I PWS (with CYFIP1 deletion) (Bittel et al. 2006; Butler et al. 2004; Doornbos et al. 2009; Milner et al. 2005; Zarcone et al. 2007).