GNRH1 and Meckel syndrome, type 1: It is worth noting that in patients with LCA or MKS, aside from the abnormal sense of smell caused by the CEP290-induced olfactory epithelium dysplasia, GnRH deficiency to varying degrees can also be detected, because the olfactory epithelium is involved in the first stage of the neuronal migration, and if the epithelium is impaired, the GnRH neurons would not reach their final residence, the hypothalamus [40].