Munc18‐3 is ubiquitously expressed, but reduced levels of Munc18‐3 are linked to obesity (Garrido‐Sanchez et al, 2013) and glucose intolerance (Oh et al, 2005; Bergman et al, 2008), mutations in VPS45 lead to severe congenital neutropenia (Vilboux et al, 2013), and mutations in VPS33B cause arthrogryposis–renal dysfunction–cholestasis (ARC) syndrome (Gissen et al, 2004). The gene discussed is VPS33B; the disease is obesity due to melanocortin 4 receptor deficiency.