Analysis of Nuclear Families with Two and more Sibs Suffering from Insulin-Dependent Diabetes Mellitus using the Method of Affected Sibs Pairs on the Basis of the Mixed Model Applying the Conditional Probability Method

ABSTRACT

An analysis has been made of 16 nuclear families (d total of 69 persons) with two and more sibs suffering from insulin—dependent diabetes mellitus (I.D.D.M.) (sibs number 32), applying the method of the affected sibs pairs on the basis of the mixed model, utilizing the conditional probability approach. 56.3% (9 from 16) diabetic sibs pairs are concordant in 2 HLA—haplotypes (expected 25%), 31.3% (5 from 16) are concordant in 1 haplotype (expected 50%) and 12.5% (2 from 16) are discordant in 2 haplotypes (expected 25%). The values under observation differed reliably from the expected (p 0.025). The statistically reliable deviation in the observed distribution of the haplotypes among the sibs pairs suffering from I.D.D.M. sibs from the theoretically expected distribution according to Mendel's law, testifies in favour of the relations of the supposed locus of this malady and the marker HLA-locus, i.e., in favour of the association of I.D.D.M. to the HLA—system.