Mutation Characteristics,Clinical Phenotype And Genetics Of NF1 Gene In ASD Children

ObjectiveTo investigate the mutation of neurofibromatosis type 1(NF1)gene in children with autism spectrum disorder(ASD),its type and its correlation with clinical phenotype,and to understand the occurrence of NF1 gene mutation in children with ASD.Methods124 children with ASD,caged 2-14 with Autism Rating Scale(CARS)≥30 and Autism Behavior Checklist(ABC)≥67,who were consulted or treated in Department of Pediatrics,Fujian Provincial Hospital from January 2016 to January 2021 were selected as the study subjects,with their biological parents,another 225 normal children in the same period were selected as the control group.The DNA was taken from the peripheral blood.Mutation detection and polymorphism analysis of Exon 12,23 and 37 of NF1 gene coding region were performed by polymerase chain reaction-single Single-strand conformation polymorphism polymorphism(PCR-SSCP),heteroduplex analysis(HA)and DNA sequencing.Childhood Autism Rating Scale and Autism Behavior Checklist were used to evaluate the clinical phenotype of children with ASD,including sensory ability,motor ability,communication ability,language ability and self-care ability.SPSS22.0 software package was used to carry out statistical calculation by multiple sample rate test and variance analysis of measurement data.P<0.05 showed significant difference.Results1.The general data of case group and control group were compared.There was no significant difference in sex composition and age between case group and Control Group by χ~2 test and t test(p>0.05).2.DNA quality test results.All the DNA samples after the first or second sample can see a bright single band,its concentration and purity met the requirements of DNA quality.3.Genotyping and detection of Single-nucleotide polymorphism.The genotype of Chr17:31206352(Exon 12),Chr17:31230280(Exon 23),Chr17:31327573(Exon 37)were diallelic polymorphism,Chr17:31206352(C>T),Chr17:31230280(A>G),Chr17:31327573(C>T),the detection rates were 98.49%,98.32%and 98.49%respectively.4.The results of HWE test showed that the gene frequency distribution of there polymorphic DNA locis in 225 normal children in this study were in line with HWE equilibrium(p>0.05),and the expected values and observed values were in good agreement,suggesting that the data could be used for further association analysis.5.Association analysis of three polymorphic locis of NF1 gene in case group,parent group and control group.chr17:31206352(exon12),chr17:31230280(exon23)and chr17:31327573(exon37)in NF1 gene showed polymorphism.By χ~2 test,there was no significant difference in allele and genotype frequencies among case group,parent group and control group(P>0.05),indicating that the three locis of NF1 gene were polymorphic,but there was no significant correlation with ASD.6.Protein structure prediction of three polymorphic gene locis of NF1 gene.The results predicted that the polymorphic site did not cause changes in protein structure.7.The relationship between the three NF1 gene polymorphisms and the clinical phenotype of ASD children:There was no significant difference in the scores of CARS and ABC between different genotypes(p>0.05).ConclusionsIn exons 12,23 and 37 of NF1 gene coding region,chr17:31206352(exon 12),chr17:31230280(exon 23)and chr17:31327573(exon 37)were polymorphic locis,but they were not significantly associated with ASD.