Which are the causes of Truncus Arteriosus?

TL;DR: Truncus arteriosus is a rare congenital heart defect caused by a failure of the single embryonic vessel to divide into the aorta and pulmonary artery during the first few weeks of fetal development. While the exact cause remains unknown for most cases, it is frequently linked to chromosomal abnormalities, most notably 22q11.2 deletion syndrome.

What causes Truncus Arteriosus to develop?

Truncus arteriosus occurs when the truncus arteriosus—a large, common vessel in the developing heart—fails to partition into two separate vessels. During normal development, a wall called the aorticopulmonary septum grows to divide this vessel. In cases of truncus arteriosus, this process is incomplete, leaving a single arterial trunk that supplies blood to both the body and the lungs. Researchers view this as a developmental error in the migration of neural crest cells, which are essential for building the heart's outflow tracts.

Is Truncus Arteriosus hereditary or genetic?

In many instances, truncus arteriosus is not inherited from parents but occurs as a sporadic developmental event. However, genetic factors play a significant role. Clinical data indicates that approximately 30% to 40% of infants born with truncus arteriosus have 22q11.2 deletion syndrome (DiGeorge syndrome). Other chromosomal variations and single-gene mutations may also contribute, though these are less common.

What are the known risk factors for Truncus Arteriosus?

Distinguishing between causes and risk factors is vital. A cause is the direct mechanism of the defect, whereas risk factors are conditions that may increase the likelihood of its occurrence. Known associations include:

• Chromosomal anomalies: Specifically 22q11.2 deletion.


• Maternal health: Pre-existing diabetes or certain viral infections during early pregnancy.


• Environmental exposures: Exposure to certain medications or substances during the first trimester.

What is current research revealing about this condition?

Current research into truncus arteriosus focuses on the molecular signaling pathways that guide heart development. Scientists are specifically studying how specific transcription factors regulate the migration of cardiac neural crest cells. As 105 people with truncus arteriosus have joined our DiseaseMaps.org community, we are gaining better insights into the long-term outcomes and patient experiences that inform ongoing clinical research.

Next steps

• Consult a pediatric cardiologist or a clinical geneticist for a comprehensive evaluation.


• Request genetic counseling to understand the risk of recurrence in future pregnancies.


• Join the DiseaseMaps.org community to connect with other families managing truncus arteriosus.


• Discuss participation in congenital heart disease registries with your medical team.

Medical disclaimer: This information is for educational purposes only and does not substitute professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Truncus Arteriosus.


• Orphanet: Common arterial trunk (Truncus Arteriosus).


• OMIM (Online Mendelian Inheritance in Man): Truncus Arteriosus, Persistent.


• American Heart Association: Congenital Heart Defects.