Genealogy of patients with congenital heart disease in isolated populations.

In isolated populations rare genetic diseases are important and relatively frequent. The objective of this study is to determine the geographical aggregates of maternal and paternal ancestors of patients with congenital heart disease (CHD) to determine whether there is an association between the different areas and types of cardiac defects. Descriptive, observational, and cross-sectional study of patients with CHD obtained consecutively in a single adult CHD unit between January 2018 and December 2019 in Gran Canaria (Canary Islands, Spain). To be included in the study, at least one of the grandparents (maternal or paternal) should be born in Gran Canaria. 258 out of 353 CHD patients met the inclusion criteria. 58% of CHD patients were male and the median age was of 28 (21-40) years old. The most frequent types of CHD were cardiac septal defects (76 patients), right side cardiac outflow tract anomalies (74 patients) and left side cardiac outflow tract anomalies (58 patients). 13% of the patients had a family history of CHD, 11% showed consanguinity and 7% had an associated polymalformative syndrome. 20% of the four ancestors were born in the same municipality and a significant association was seen between two areas of Gran Canaria, orographically related, and right-side cardiac outflow tract anomalies (P<0.001). In conclusion in patients with tetralogy of Fallot and/or pulmonary valve stenosis/atresia an ancestry's geographic aggregation was seen.