The importance of HLA genes to susceptibility in the development of juvenile diabetes mellitus. A study of 93 patients and 68 first degree blood relations.

The importance of genetically determined antigens of the HLA system in etiology and pathogenesis of juvenile onset diabetes (JOD) was studied in 93 JOD-patients and 68 blood relations. A close association was found between JOD and B-locus antigens B8 and Bw15, and C-locus antigen Cw3. Patients positive for one of these antigens have a 2-3 times -- and those positive for both B8 and Bw15 -- a 8.6 times greater chance of developing JOD, Evidence for a genetic heterogeneity between childhood type and later onset JOD could be obtained. B8 seems to play a particularly important role in childhood-type diabetes, whereas in the later onset JOD the antigens Cw3 and/or Bw15 might possibly represent an additional predisposing factor. Family studies have revealed a close correlation between glucose intolerance and those genes associated with JOD in blood relations below age 35. HLA-B7 which could be detected in that group of blood relations, and which was found statistically decreased in JODs might even exert some protective role. Incidence of haplotye identity in glucose intolerant siblings was almost three times higher than expected. These data provide evidence for the existence of a genetic basis which determines the susceptibility to develop JOD.