Editing Tetralogy of Fallot (section)

== Epidemiology ==
The prevalence of tetralogy of Fallot is estimated to be 0.02–0.04%, which corresponds to approximately 200 to 400 cases per million live births.<ref name="pmid152344302">{{cite journal | vauthors = Child JS | title = Fallot's tetralogy and pregnancy: prognostication and prophesy | journal = Journal of the American College of Cardiology | volume = 44 | issue = 1 | pages = 181–183 | date = July 2004 | pmid = 15234430 | doi = 10.1016/j.jacc.2004.04.009 | doi-access = free }}</ref><ref name="NORD">{{Cite web|title=Tetralogy of Fallot|url=https://rarediseases.org/rare-diseases/tetralogy-of-fallot/|access-date=2021-11-21|website=NORD (National Organization for Rare Disorders)|language=en-US|archive-date=2021-11-10|archive-url=https://web.archive.org/web/20211110172804/https://rarediseases.org/rare-diseases/tetralogy-of-fallot/|url-status=live}}</ref> It accounts for 7–10% of all congenital heart abnormalities, making it the most common cyanotic heart defect.<ref name="Roos-Hesselink_2017" />{{rp|100–101}} Although males and females were initially believed to be affected equally, more recent studies have shown TOF affects males more than females.<ref name="NIH2011What2">{{cite web|date=1 July 2011|title=What Is Tetralogy of Fallot?|url=http://www.nhlbi.nih.gov/health/health-topics/topics/tof/|url-status=live|archive-url=https://web.archive.org/web/20161004225713/http://www.nhlbi.nih.gov/health/health-topics/topics/tof|archive-date=4 October 2016|access-date=2 October 2016|website=NHLBI}}</ref><ref name="NORD" /> About 1 in 100 newborns is diagnosed with a congential heart defect, of which 10% are diagnosed with TOF.<ref name="NORD" /> Genetically, it is most commonly associated with Down syndrome and DiGeorge syndrome.<ref name="Roos-Hesselink_2017" /><ref name="Francois_2016"/> Down syndrome and other chromosomal disorders are known to occur alongside congential heart defects such as TOF.<ref name="NORD" />