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.

Objective: Renalase is an enzyme that circulates in the blood and modulates the cardiac function, sympathetic tone and systemic blood pressure. It can be synthesized in the kidneys, liver and cardiomyocytes. The active enzyme degrades circulating catecholamines, causing a significant fall in blood pressure. Changes in renalase concentration in hemodialysis patients may explain the frequent occurrence of hypertension among patients with end-stage kidney disease. The aim of this study was to asses’ serum renalase levels in hemodyalisis patients and apparently healthy subjects, and association of renalase and blood pressure in patients group. Design and method: 160 subjects were recruited in the study: 120 with end-stage renal disease, divided into two groups, according to their blood pressures (normotensive and hypertensive), and 40 apparently healthy individuals matched in age and sex. Blood pressure was measured before and after a hemodialysis session. The target values, according to ESH/ESC guidelines, were lower than 140/90 mmHg before, and 130/90 mmHg after hemodialysis. The blood for the estimating serum renalase concentration was taken before dialysis. Enzyme-linked immunosorbent assay (ELISA) kit with monoclonal antibody specific to renalase, was used. Results: Mean serum renalase levels in normotensive as well as hypertensive hemodialysis patients were significantly higher compared to control group {89.32 (45.77–170.22) and 42.7 (32.79–63.35) &mgr;g/ml, respectively; p < 0.0005}. No significant difference of renalase levels among normotensive and hypertensive patients was noted {64.04 (40.76–173.84) and 91.86 (56.77–149.75.35)&mgr;g/ml; (p > 0.05)}. There was a highly significant difference between systolic and diastolic pressure measured before and after the dialysis in normotensive and hypertensive groups of patients (p < 0.0005). It was noted that there is a significant, negatively directed association between patients’ age at the beginning of dialysis and the duration of hemodialysis. Also, the correlation between blood pressure and renalase activity among normotensive and hypertensive hemodialysis patients was not shown (p > 0.05). Conclusions: Further studies are needed to define the role of renalase and its complex pathophysiological link with blood pressure regulation, kidney function and sympathetic tone. Renalase may become a new therapeutic target that leads to a better prognosis for patients with end-stage kidney disease.