PROKR2 and congenital hypogonadotropic hypogonadism: A total of 43 rare or novel variants were found in 20 genes associated with congenital hypogonadotropic hypogonadism CHH (ANOS1, CCDC141, CHD7, DUSP6, FEZF1, FGFR1, FLRT3, FSHB, GNRHR, HS6ST1,LHX3, LHX4, PLXNA3, PROK2, PROKR2, PROP1, RNF216, SEMA3A, SEMA3F and SPRY4).