A1 is encoded by the ANOS1 gene, former KAL1 (de Castro et al. 2017), whose mutation produces the Kallmann syndrome (KS) that is characterized by hypogonadotropic hypogonadism and anosmia, presumably as a result of defects in neuronal migration and axonal targeting (Tsai and Gill 2006; de Castro et al. 2014). Here, ANOS1 is linked to Kallmann syndrome.