Association of Parental Age and the Type of Down Syndrome on the Territory of Bosnia and Herzegovina

Background: Advanced paternal and/or maternal age is a classic risk factor for Down syndrome. The aim of the study was to investigate the frequency of Down syndrome types in children and its association with maternal and paternal age in Bosnia and Herzegovina. Subjects and Methods: The cross sectional, observational study included 127 children, 49 girls and 78 boys, aged 1-180 months suspected to have Down syndrome, admitted to the Centre for Genetics, Faculty of Medicine University of Sarajevo, for cytogenetic analysis and differential diagnosis of Down syndrome during the period from January 2010 to May 2015. Standard method of 72 hours cultivation of peripheral blood lymphocytes has been applied. The accepted level of statistical significance was p<0.05. Study Results: The most common type of Down syndrome was standard trisomy (86.6%), comparing to translocation and mosaicism (7.1%; 6.3%, respectively). The highest frequency of Down syndrome cases was in mother and father’s group from 30-39 years old (57; 57 children, respectively) compared to mother and father’s groups with younger than 30 (44; 29, respectively) and 40 and older (26; 41, respectively). The significant difference was found in maternal age between translocation and mosaicism groups (p=0.036). Difference between parental years and type of Down syndrome was significant when Standard trisomy 21 and translocation (p=0.045), as well as mosaicism and translocation (p=0.036), were compared. Conclusion: The most common type of Down syndrome was standard trisomy 21, with highest occurrence in parents from 30 to 39 years old. Parents were the youngest in translocation group. Obtained results suggest that multidisciplinary approach to identifying the trigger for trisomy appearance and the influence of maternal age is required.