Abstract: Objective To study the clinical characteristics of idiopathic hypogonadotropic hypogonadism（IHH） and its related gene mutations in females. Methods Clinical data and laboratory findings about 4 IHH patients were analyzed.Sequences of the GnRHR,KAL1 and FGFR1 genes in 3 patients and controls were detected by PCR. Results No secondary sex characters were found in the 4 female IHH patients who had a normal karyotype,underdeveloped sexual phenotype,low gonadotropic hormones and estradiol levels.Brain MRI showed normal olfactory bulbs and sulci.No mutation was observed in the GnRHR gene.Two nucleotide polymorphisms were detected in KAL1 gene of cases 3 and 4.The 251A in exon 3 of the FGFR1 gene was transformed into T（Glu84Val）. Conclusion Mutation of the FGFR1 gene occurred only in 1 of the 3 patients in this study,indicating that other factors may lead to IHH.