We investigated whether the gonadotropin deficiency observed in nes-Cre;Dmxl2–/wt mice was due to GnRH deficiency, by quantifying GnRH mRNA levels in the hypothalamus of nes-Cre;Dmxl2–/wt mice and comparing them with those of WT mice. The gene discussed is DMXL2; the disease is hyperinsulinemic hypoglycemia, familial, 4.