Exploration On The Pathogenic Genes And Mechanisms Of Congenital Vertebral Malformations

Objectives:Congenital vertebral malformation is a group of birth defects characterized by abnormal vertebral body shape,which could present as congenital scoliosis,Klippel-Feil syndrome and so on.Congenital vertebral malformation has the clinical characteristics of high incidence,rapid progression,and severe deformity.The exploration of genetic background and the discovery of new pathogenic genes are both research hotspots in the field of etiology of this disease.CSF1R gene is a newly discovered pathogenic gene of congenital vertebral malformation.The highly pathogenic variants located at the carboxyl end of protein can lead to CVM through gain of function effect.The objectives of this study are:1)Screening the highly deleterious variants of CSF1R gene in the CVM patients,analyzing their clinical phenotypic characteristics.2)Analyzing the coding genes of important proteins related to the CSF1/CSF1R signaling pathway,screening the highly pathogenic variants of those genes.3)Identifying novel candidate pathogenic genes,preliminarily verifying the pathogenicity of those genes’deleterious variants through functional experiments.Method:1)We have recruited a research cohort consisting of 873 CVM patients,analyzed the whole exome sequencing data of the cohort patients,and screened for highly pathogenic variants of CSF1R gene;2)We analyzed the clinical phenotype of carriers of CSF1R highly pathogenic variants,and summarize the clinical characteristics of those CSF1Rrelated congenital vertebral malformation patients;3)According to the public databases,we established a CSF1R-related gene list and screen for deleterious variants in those genes;4)We have performed immunohistochemical experiments and western blot experiments to explore the pathogenicity and pathogenesis of CSF1R-related genes’variants.Result:1)In this study,we identified six heterozygous deleterious rare variants in CSF1R,three of which were reported for the first time.2)CSF1R-related congenital vertebral malformations patients mostly exhibit thoracic vertebral malformations.The severity of the disease is related to the deleteriousness of variants.3)The CVM patients in the cohort carried 23 deleterious rare variants in 12 genes,which might be related to CSF1/CSF1R signaling transduction.Among those genes,PHLPP2 is identified as important candidate gene of CVM.The experiments have proved that PHLPP2 is expressed in vertebral body in the early embryonic development.The highly pathogenic variants of this gene can reduce the expression level of PHLPP2.Conclusion:CSF1R-related patients with congenital vertebral malformation displayed distinctive clinical characteristics.The abnormality of CSF1/CSF1R signal transduction pathway is an important factor in pathogenesis of those patients.PHLPP2,a gene related to CSF1/CSF1R signal transduction,was identified as an important candidate pathogenic gene of CVM.