GNRH1 and central precocious puberty: To confirm the onset of CPP, the current guidelines (Carel et al., 2009; Bangalore Krishna et al., 2019) recommend the measurement of plasma LH using sensitive chemiluminescent or electrochemiluminescent immunoassay (CMIA or ECLIA) reagents, before or after a GnRH stimulation test (Kastin et al., 1972a,b).