TYPE I DIABETES MELLITUS
(Insulin-Dependent Diabetes Mellitus [IDDM]; Juvenile-Onset Diabetes)
ETIOLOGY AND PATHOGENESIS.
the sharply diminished secretion of insulin.
The mechanisms : autoimmune destruction of pancreatic islets in predisposed individuals. increased prevalence among persons with such disorders as Addison disease, Hashimoto thyroiditis, and pernicious anemia.
increased frequency of certain HLAs, : HLA-B8, -DR3, -B15, and -DR4.
Inheritance of HLA-D3 or -D4 antigens : two- to threefold increased risk
Inheritance of both D3 and D4 : sevenfold to 10-fold.
A genetic type of properdin factor B (BfF1) : more than 20% of type I
The homozygous absence of aspartic acid at position 57 of the HLA-DQ beta- chain (nonAsp/nonAsp) : 100-fold relative risk for developing type I diabetes.
arginine at position 52 of the DQ alpha- chain susceptibility to I nsulin-dependent diabetes mellitus.