Several studies showed that anti-TNF-α drugs still have variable efficacy for HPS-related IBD (Erzin et al., 2006; Felipez et al., 2010; Grucela et al., 2006; Kouklakis et al., 2007; Yoshiyama et al., 2009). The gene discussed is TNF; the disease is Hermansky-Pudlak syndrome.