In recent years, to unveil new CHH causative genes, two main approaches have been adopted: i) screening of CHH patients with high throughput techniques and functional validation of the identified genes/variants by ad hoc in vitro or in vivo models; and ii) basic science-driven identification and validation of candidate genes involved in GnRH neuron physiology and the subsequent search for mutations in patients via interrogation of available cohorts of patients. Here, GNRH1 is linked to cartilage-hair hypoplasia.