Genealogical reconstruction of myotonic dystrophy in Istria: founder effect in Svetvinčenat parish

Abstract

Historic and medical science are closely related through a specific medical branch - the history of medicine. Recent development of medical and population genetics has provided history with new methodologies, meanwhile historic methodology is succesfully used in explanation of genetic phenomena. In this study the genealogical reconstruction of Istrian families affected by myotonic dystrophy was performed using mainly historic sciences methodology. High prevalence of myotonic dystrophy of 18.1 per 100,000 has been found in Croatian region Istria, a region where a great mixture of nations occurred over the last centuries. The objective of this study was to test the hypothesis of common ancestry in Istrian myotonic dystrophy families. Pedigrees were constructed on the basis of extensive family history obtained from the patients in all Istrian myotonic dystrophy families. Church records were consulted in order to improve genealogical reconstruction. A common ancestor couple for three of seven Istrian nucleus families (nine families identified, two of them moved to Istria in the last decades) was found eight generations backward in the first half of 18th century: they were living in a village Bokordici, Savicenta parish. In spite of finding an explanation of the high DM prevalence in Istria, we argue that this phenomenon is not sufficient to prove the evidence of founder effect in Istria. Genealogical reconstruction supported by church records has provided invaluable information in demonstration of myotonic dystrophy origins in Istria.