Detection And Analysis Of Glycometabolism Related Genes In Children Diabetes

Objective In recent years,the number of children with Diabetes Mellitus(DM)is increasing.DM has become one of the important diseases that endanger physical and mental development of children.According to the American Diabetes Association's “Standards of Medical Care in Diabetes” in 2018,children with diabetes by etiology can be classified mainly into Type 1 Diabetes Mellitus(T1DM),Type 2 Diabetes Mellitus(T2DM)and other types of diabetes.T1 DM is an islet beta cell mediated autoimmune disease and is also the major type of childhood DM.Most T1 DM patients can detect islet autoantibodies in the blood,while a few patients have negative antibody tests.Patients with antibody-negative diabetes may include maturity onset diabetes of the young(MODY),neonatal diabetes mellitus(NDM),and genetic syndromes associated with diabetes.In this study,we used high-throughput sequencing and Sanger sequencing to screen glucometabolism related genes in islet autoantibody-negative children with diabetes.This study would shed light on the etiology and mechanism of antibody-negative diabetes,and deepen the understanding of antibody-negative diabetes,which will lead to a comprehensive analysis of genotypes and phenotypes of antibody-negative diabetes,and help further precision treatment in these patients.Methods A total of 32 subjects with antibody-negative diabetes(ICA,GADA,IA-2)and fasting C-peptide?0.3 ng/ml were collected as experimental group.Another control group was 32 cases of T1 DM.After informed consent was obtained,patient history data and a detailed physical examination were collected.The peripheral blood DNA was extracted from patients and their parents for high-throughput sequencing of glucose metabolism related genes.Sanger sequencing validation was performed on patients and their families for the possible pathogenic mutations.The relative indexes such as birth weight,fasting C-peptide,onset time,glycated hemoglobin at the first visit,age,family history,incidence of ketoacidosis(DKA),dose of insulin were also collected and underwent statistical analysis.Results 1.In the 32 cases of antibody-negative diabetes,possible related mutations was detected in 21 cases.There were 11 genes related to diabetes mellitus,4 were pathogenic,3 were likely benign and 4 were with uncertain significance.There were 12 genes related to susceptibility to diabetes.2.There were significant differences in the BMI,fasting C-peptide,DKA incidence and insulin dosage between the group with pathogenic mutation and the group with positive islet autoantibody(P<0.05).There were significant differences in the fasting C-peptide,glycated hemoglobin at the first visit and insulin dosage between the group with no detected mutation and the group with positive islet autoantibody(P<0.05).There were significant differences in the fasting C-peptide,DKA incidence and glycated hemoglobin at the first visit insulin dosage between the group with pathogenic mutation and the group with no detected mutation(P<0.05).3.ROC analysis revealed that the optimal cut-off value of fasting C-peptide to predict diabetic kidney damage was 0.64ng/ml,for this cut-off value,specificity was 85.7%,sensitivity was 92.7%.Area Under the curve was 0.735.Conclusions 1.In antibody-negative type 1 diabetes children,there are monogenic diabetes.However,monogenic diabetes genetic variation may not be the main cause of antibody-negative diabetes.2.Fasting C-peptide combined with BMI,DKA incidence,Hb A1 c,insulin dosage can be used as a marker of antibody-negative diabetes,which is beneficial to distinguish type 1 diabetes and others,can improve the detection rate of monogenic diabetes.3.Compared with type 1 diabetes,monogenic diabetes and type 2 diabetes may be lower birth weight,body fat,higher fasting C-peptide,lower incidence of DKA,insulin dosage less.4.This study found that GCGR c.118G> A p.G40 S exists in Chinese patients with T2 DM,considering that the locus is related to the susceptibility to T2 DM in China.5.Our study found a case of non-reported ELN nonsense mutation(G611 *),this mutation may be related to glucose metabolism,this need for further more research to do.6.This study found an unreported frameshift mutation of LIPC,which had a great effect on protein function and was related to glucose and lipid metabolism.This requires further research to prove our results.