Abstract: Kallmann syndrome（KS） is a complicated human genetic disorder with congenital hypogonadotropic hypogonadism（HH） and anosmia or hyposmia. It is also a genetically and clinically heterogeneous disease. Eighteen genes were found to be related to KS，including KAL1，FGFR1，PROKR2，PROK2，CHD7，FGF8，WDR11，NELF，HS6ST1，SEMA3A，HESX1，SOX10，IL17RD，FGF17，SPRY4，DUSP6，FLRT3 and AXL. However，only six genes（KAL1，FGFR1，PROKR2，PROK2，CHD7 and FGF8） were identified, which covered approximately 30% of the KS cases. Actually, genic mutations in about 70% of KS cases were unknown. The clinical assessment and genetic aspects of KS, as well as its partial reversibility and early diagnosis, were hereby reviewed.

Key words: Kallmann syndrome, Molecular biology, Phenotype, Genetic heterogeneity, Diagnosis