[Probability of an association between HLA- and DR-antigens in nuclear families of patients with insulin-dependent diabetes mellitus].

Insulin dependent diabetes mellitus (IDDM) is known to associate with various antigens and alleles of the HLA-system: DR3, DR4, and DQ-determinants. However penetration of the HLA-genes, predisposing to disease, is low, suggesting a possible role of additional genes outside the HLA-system in IDDM development. Among such genes there can be a group of heavy chain Ig genes (the Gm-system). The frequency of antigens of the Gm-system C1m(1) and C1m(2) and antigens of loci A, B, C and DR of the HLA-system was investigated in 92 Russians divided into 3 groups: 1 - IDDM patients from nuclear families (n = 35); 2 - their relatives of the 1st degree of kinship (n = 34); 3 - a random sampling (n = 23). The results obtained by A. A. Lopatenok and O. S. Budyakov (1973) were used as control data. No significant difference (p greater than 0.05) was found while comparing the frequency of Gm-phenotypes in IDDM patients from nuclear families with DR 4/X and in IDDM patients from nuclear families with another DR-phenotype, nor any significant difference was noted while comparing the frequency of Gm-phenotypes in IDDM patients from nuclear families and in patients from a random sampling with the HLA-phenotype DR 4/X. Thus the relationship of the Gm-system with IDDM through interrelationship with the HLA-DR-genes was undetectable. A conclusion was made that factors of the Gm-system played no significant role in predisposition to IDDM and could not be used as its genetic markers.