User:Ksoccer22/Tetralogy of Fallot

Epidemiology
Tetralogy of Fallot is a congenital heart disease (occurs during the development of the fetus) affecting 1 in every 2,518 babies each year. One third of patients under the age of 15 that have a congenital heart condition have Tetralogy of Fallot, so that of the one percent of babies born with a congenital heart defect, of that 1%, 10% of babies these have Tetralogy of Fallot. It is most common in children living past neonatal age, but is diagnosed during fetal life as early as seven weeks into the pregnancy or the immediate weeks or months following birth typically, and is the most common cyanotic heart diseases.

Depending on the severity of the disease, Tetralogy of Fallot is sometimes not found in patients until adulthood. The disease is found in male and female babies equally. As for siblings, the incidence is low between 1-5%, but if a parent has Tetralogy of Fallot, their future child has a much higher chance of getting the disease. Tetralogy of Fallot is sporadic and unfamiliar, however studies suggest that it is multifactorial through genetic and environmental triggers. Patients with Tetralogy of Fallot can present a higher frequency of non-cardiac congenital diseases. This can include the association with congenital scoliosis, which can lead to a missing vertebrae depending on the severity of the pressure on the ventricles. Other diseases that have presented more commonly in individuals with Tetralogy of Fallot are more likely to born with a cleft palate, cleft lip, gastrointestinal and renal lesions. Some patients with Tetralogy of Fallot also have other heart defects.

Causes
The cause is unknown but it is know that the condition stems from an error in the heart separating into the normal chambers and valves of the heart and it leaves a small part of chromosome 22 missing, which is a coherent chromosome to Down Syndrome. Children with Down Syndrome are more likely to be diagnosed with Tetralogy of Fallot. The q11 region of the chromosome is deleted in 25% of babies with Tetralogy of Fallot. The disease could also be potentially linked to fetal alcohol syndrome, velocardiofacial syndrome and Digeorge's Syndrome. Maternal pregestational diabetes, viral illnesses during pregnancy, a pregnancy over the age of 40, and poor nutritional habits during pregnancy are also found to be risk factors for Tetralogy of Fallot. Environmental factors such as poor air quality can also be a factor to increase the incidence of Tetralogy of Fallot. There is an increased chance of mortality when the infant has an extracardiac malformation, and if left untreated the mortality rate of Tetralogy of Fallot is 50% by the age of six years old.