Long-term Trends in the Prevalence of Congenital Heart Defects in Patients with Down Syndrome in Southern Poland

INTRODUCTION: Down syndrome is one of the most common chromosomal abnormalities in humans. Patients have typical dysmorphic features and various congenital malformations. Congenital heart defects were reported as the most common of the latter, occurring in approximately 50% of the cases. THE AIM: We aimed to analyse the long-term trends in the prevalence of Down syndrome and related heart defects in the population of southern Poland (Krakow region) MATERIAL AND METHODS: We analysed 500 consecutive patients with Down syndrome who were born from 2006 through 2017 and were diagnosed at the Department of Medical Genetics, Jagiellonian University. Next, we compared our results with the data obtained in previous regional studies. RESULTS: The prevalence of Down syndrome in the assessed period was 1.65 per 1,000 live births and was similar to the historical prevalence in our region. Cardiac malformations were detected in 57.6% of the patients and the common atrioventricular canal (CAVC) was the most frequent anomaly (35.1%). However, detailed analysis of the frequency of severe heart defects that usually require prompt surgical treatment in the course of infancy revealed that the percentage of CAVC has been significantly lower in recent years (p=0.033). CONCLUSIONS: The prevalence of Down syndrome and the overall frequency of congenital heart defects have not significantly changed in recent years. However, the frequency of CAVC has decreased, which could be related to the technical progress in prenatal detection of this severe anomaly, and to the subsequent elective terminations of affected pregnancies. Further population studies are required to confirm the presence of this trend and elucidate its background.