Insulin gene profile cycles with season of birth of future diabetic children and their relatives

Abstract

Background: HLA class II gene pattern and IA-2A antibody positivity, revealing selected risks for prediction of type 1 diabetes mellitus (DM1), were previously shown to be cycling roughly in parallel with seasonally fluctuating frequencies of births of future diabetic children. Is this also true for insulin genotyping? Is this also true for births of the healthy close relatives of children with DM1? Patients and Methods: In 98 Slovak children with DM1 and in 60 healthy parents and siblings, two single nucleotide polymorphisms of the insulin gene (-23 Hph I; +1127 Pst I) were typed. Results were expressed as score 0 (maximal risk) up to 2 (minimal risk or protection), or 0-4 for the sum of both scores. Birth seasonality of these risk scores was tested by Halberg cosinor regression. Results: Results were similar for the two alleles; therefore, the summed risk score was evaluated. The DM1 risk from the insulin gene pattern in births of future diabetics cycled significantly semi-annually, with maxima around the spring and autumn equinoxes. In the relatives, a significant annual and extremely pronounced quarterly peaking rhythm was found, with maximum risk in births around the autumn equinox and shortly after the winter solstice. Significant protection peaks are present in late winter, spring and summer. Conclusion: The highest frequency of Coxsackie infections in tht Slovakian child population, and of 'diabetic' births and manifestations, found earlier together with maximal risks from HLA II and IA-2A antibodies in late summer and early autumn, is now confirmed also for the insulin gene pattern in diabetic children and even also for their healthy close relatives. © Freund Publishing House Ltd.