[Analysis of nuclear families with two or more patients with insulin-dependent diabetes mellitus with diabetic siblings]. / Analiz iadernykh semei s dvumia i bolee bol'nymi insulinzavisimym sakharnym diabetom sibsami.

HLA haplotype distribution was analyzed in nuclear families of patients with insulin-dependent diabetes mellitus. Sixteen families with two or more diabetic siblings were examined, a total of 69 subjects, 33 of these diabetic siblings and 36 normal subjects (siblings and parents). The data were processed using the involved sibling pairs method based on a mixed model making use of a conditional probability approach. The ratio of diabetic sibling pairs concordant by 2 haplotypes, 1 haplotype, and discordant by 2 haplotypes was 9:5:2 vs. 1:2:1 expected according to Mendel's accidental distribution (p < 0.025). Increased incidence of siblings concordant by 2 haplotypes proves the presence in the HLA domain of one or several genes responsible for the development of diabetes mellitus. Siblings identical by two HLA haplotypes with the diabetic proband are at a higher risk of developing this disease.

[Probability of an association between HLA- and DR-antigens in nuclear families of patients with insulin-dependent diabetes mellitus]. / Veroiatnost' assotsiatsii mezhdu HLA- i DR-antigenami v iadernykh sem'iakh bol'nykh insulinzavisimym sakharnym diabetom.

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.