Molecular Etiology Of Exon Sequencing In Family Type 2 Diabetes Mellitus

Objective:To explore the possible pathogenic genes and gene mutation sites in family type 2 diabetes mellitus.Methods:Seven immediate family members with at least three generations of diabetes-were collected.The proband was a male patient with a ten-year history of diabetes in the second generation.Then peripheral venous blood of family members were collected,and blood cells and plasma were separated.The whole blood genomic DNA rapid extraction kit was used to extract blood cell DNA,and then the whole genome exon sequencing and bioinformatic data analysis were performed to find possible pathogenic genes and gene mutation sites in the family.Results:Among the members of this family,three generations of immediate family members have diabetes.The characteristics of diabetes mellitus are consistent with polygenic inheritance.Whole genome exon sequencing and bioinformatic data analysis showed that there were 8383 exon DNA mutations in all six diabetic family members,while not any mutation was found in a non-diabetic control member.Among them,there were 7603 single nucleotide polymorphism mutation sites and 780 insertion-deletion mutation sites.Through the significant analysis of the unique SNP and Indel sites in the family of diabetes,22 mutation sites with significant and moderately high biological functions were found finally,including 10 single nucleotide polymorphism mutation sites and 12 insertion-deletion mutation sites.The corresponding genes of 22 mutation sites were mapped into the KEGG pathway,and the PNLIPRP1 gene and the CAMKK2 gene were finally mapped into the KEGG glycolipid metabolism pathway.There are a homozygous mutation of rs2305205[c.812C>T?p.Ala271Val?]in the PNLIPRP1 gene of the proband,and a homozygous mutation of rs778701848[c.1612₁614dupAAA?p.Lys538dup?]in the CAMKK2 gene.The proband parents have a heterozygous mutations in PNLIPRP1 gene and CAMKK2 gene separately.Mutation of the PNLIPRP1 gene may attenuate the role of pancreatic lipase-associated protein 1 in competition with pancreatic triglyceride lipase?PTL?for colipase,resulting in increased PTL activity,enhanced fatty acid digestion and absorption,and increased body fat content,which in turn causing insulin resistance.Mutation in the CAMKK2 gene may inhibit the downstream AMPK pathway,leading to decreased anti-inflammatory and autophagy,abnormal glycolipid metabolism,promoted islet ? cell apoptosis and blocked insulin signaling,and eventually lead to increased blood glucose.In summary,the PNLIPRP1 gene rs2305205[c.812C>T?p.Ala271Val?]mutation and CAMKK2 gene rs778701848[c.1612₁614dupAAA?p.Lys538dup?]mutation may be the pathogenic genes of diabetes in this family members.Conclusion:In this study,whole genome exon sequencing and bioinformatic data analysis showed that a rs2305205[c.812C>T?p.Ala271Val?]mutation in the PNLIPRP1 gene and a rs778701848[c.1612₁614dupAAA?p.Lys538dup?]mutation in the CAMKK2 gene may be associated with the pathogenesis of type 2 diabetes in this family.