CHAPTER ONE : INTRODUCTION
Diabetes is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. The chronic hyperglycemia of diabetes is associated with long-term damage, dysfunction, and failure of different organs, especially the eyes,kidneys,nerves,heart, and blood vessels. (ref ) Several pathogenic processes are involved in the development of diabetes. These range from autoimmune destruction of the B-cells of the pancreas with consequent insulin deficiency to abnormalities that result in resistance to insulin action. ( Harrison 1992 ) . Whereas type 2 DM is the most common of diabetes , its specific etiology is not yet known . Its frequency varies in different racial and ethnic subgroups and is often associated with a strong familial , likely genetic predisposition more than autoimmune type 1 DM ( Alberti & Zimmet 1998 ). …show more content…
Susequent analysis on human leucocyte antigen (HLA) region shows that HLA-DRB1 and –DQB1 genes have the strongest association with type 1 diabetes . HLA class II genes contribute to the genetic susceptibility to type 1 DM , and susceptible and protective alleles and haplotypes were implicated in the pathogenesis of type 1 diabetes ( ref ) .Genetic factors are important in the etiologty of diabetes mellitus , as known by marked differences in susceptibility in different ethnic groups and by studies in monozygotic twins where concordance rates for type 2 diabetes and for type 1 diabetes were 100% and 30% respectively (ref ) . Many genes are shown to be involved and the chance of developing diabetes is also influenced very powerfully by environmental factors ( Frier and Fisher 2006 )