GNRH1 and Kallmann syndrome: PCSK1 and POLR3B are associated with normosmic CHH (Pepin et al., 2018; Richards et al., 2017), but FGF17 mutations are associated with KS and anosmia, which implies a role during early GnRH neuron migration from the olfactory placodes as well (Valdes-Socin et al., 2014).