GNRH1 and hypogonadism: In these animals Dicer, an RNAse-III endonuclease essential for miRNA biogenesis (Bernstein et al., 2001), is selectively inactivated in GnRH neurons resulting in absence of puberty, and severe hypogonadism and sterility in adulthood caused by persistent GnRH deficiency (Messina et al., 2016).