On the genetic heterogeneity of juvenile hyperglycemia.

We have briefly discussed immunogenetic studies of families with hyperglycemia which suggest the existence of at least four types of the disease: a) juvenile, insulin-dependent, ketosis prone diabetes determined by an autosomal recessive gene with 50% penetrance and in linkage with the HLA; b) juvenile, insulin-dependent, ketosis prone diabetes probably determined by an autosomal dominant gene; c) unidentified types of juvenile, insulin-dependent diabetes whose pathogenesis may be related to the HLA associations reported; and d) maturity onset type of hyperglycemia in the young, probably determined by an autosomal dominant gene. There are probably other forms of juvenile hyperglycemia. Some may depend on genes unrelated to the HLA, others may be mostly or totally environmental, rather than genetic.