Children at High Risk of Diabetes Mellitus: New York Studies of Families with Diabetes and of Children with Congenital Rubella Syndrome

The frequency of Type I, or insulin-dependent mellitus (IDDM) in the general population is approximately 1 in 600 individuals. By contrast, in families where one child has IDDM, the likelihood that another child will develop IDDM is about 100 times higher. This population, at high risk for the development of IDDM, seemed an ideal group in which to identify some of the factors which might precede the development of clinically apparent IDDM. IDDM is clearly a multifactorial disease. The existence of a gene or genes predisposing to diabetes and mapping within or very near the HLA locus on chromosome six has been suggested by several different investigators. In addition, environmental agents also appear to be needed to “trigger” the predisposition towards overt disease since concordance for monozygotic twins is estimated at only approximately 30%. Convincing evidence has accumulated over the last several years that the mechanism of the expression of the genetic susceptibility is an autoimmune destruction of the pancreatic beta cells.