The Identified And Functional Studies Of GLI3 Mutations In Chinese IHH Patients

Objectives: Idiopathic Hypogonadotropic Hypogonadism(IHH)is a symptom characterized by partially or even completely absent adolescent development associated with inappropriately low gonadotropin and sex steroid levels within the hypothalamic-pituitary-gonadal axis.Generally,the disease was divided into two categories as Kallmann Syndrome(KS)or normal IHH with normal sense of smell(nIHH)according to the special clinical manifestation of anosmia.IHH is deemed as a rare reproductive dysfunction disorder with genetic heterogeneity.Abundant studies found that the pathogenic genes may inherit from parents with the Mendelian inheritance patterns,including X-linked,autosomal recessive,and autosomal dominant,or the other more complex oligonucleotides genetic models.However,the pathogenic mechanism of the genes is not completely clear.In recent years,GLI3 has been identified as the pathogenic gene of IHH.This has been verified in foreign populations.In this study,we screened GLI3 gene mutations in 177 Chinese IHH patients,and further studied the related functional alterations to explore potential pathogenic molecular mechanisms.Methods: In this study,we screened GLI3 mutations in Chinese IHH patients by using whole exome sequencing.We detected the activity of newly discovered GLI3 mutants by using luciferase reporter gene.We detected the protein expression level by using western blot.And we detected the subcellular localization by immunofluorescence.Results:1.7 patients(3.9%)were identified to carry different GLI3 mutants,which were C935 T,A1843T,2487-2501 DEL,C2767T,C3278 T,G4007A and T4639 A,among 177 patients diagnosed with IHH.All those were novel and harmful mutation sites.2.Among the 7 probands,28.6%(2/7)probands were nIHH and71.4%(5/7)probands were KS;85.7%(6/7)probands carried other pathogenic gene mutations;In addition to abnormal reproductive system development,28.6%(2/7)probands had other clinical phenotypes.3.There were no significant differences in activity level,protein expression and subcellular localization between the 7 mutants and the wild type in vitro.Conclusions:1.The frequency of GLI3 mutations in Chinese IHH patients was3.9%,lower than the US data 4.1% in 2016.2.GLI3 seems to be insufficient to cause IHH alone and tends to act in oligogenic inheritance patterns with other mutations.