Is Truncus Arteriosus hereditary?

Truncus arteriosus is a rare congenital heart defect that is generally considered multifactorial rather than strictly hereditary, meaning it arises from a complex interaction of genetic and environmental factors. While most cases occur sporadically as de novo mutations without a family history, a small subset of cases is associated with identifiable genetic syndromes, such as 22q11.2 deletion syndrome.

Is Truncus Arteriosus considered a hereditary condition?

Most instances of truncus arteriosus are not inherited from parents; instead, they occur as isolated, spontaneous events during fetal development. While the condition is genetic in the sense that it involves developmental gene signaling, it is rarely "hereditary" in the sense of being passed down through generations in a clear Mendelian pattern. However, because truncus arteriosus can be linked to chromosomal anomalies, clinical evaluation is essential to determine if an underlying syndrome is present.

What is the role of genetic testing in Truncus Arteriosus?

Genetic testing is often recommended for infants diagnosed with truncus arteriosus to identify potential underlying causes. Common findings include:

• 22q11.2 deletion syndrome (DiGeorge syndrome): Found in approximately 10–30% of patients with truncus arteriosus.


• Chromosomal Microarray (CMA): The standard test to look for deletions or duplications of genetic material.


• Exome Sequencing: Used in some cases to investigate rare, single-gene mutations if other tests are negative.

What are the risks for future pregnancies?

For parents who have had one child with non-syndromic truncus arteriosus, the recurrence risk for future pregnancies is generally low, estimated at approximately 1–3%. If the truncus arteriosus is found to be part of a larger genetic syndrome, the recurrence risk may be significantly higher, depending on the specific inheritance pattern of that syndrome. Genetic counseling is strongly advised for families planning future pregnancies to provide personalized risk assessments based on the specific genetic findings of the affected child.

Next steps

• Consult with a clinical geneticist to discuss whether chromosomal microarray testing is appropriate for your family.


• Connect with the 105 members of the truncus arteriosus community at DiseaseMaps.org to share experiences and resources.


• Request a referral to a fetal cardiologist if you are currently pregnant and have a family history of congenital heart disease.

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice; please consult with a qualified healthcare professional for diagnosis and treatment.

References

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


• Orphanet: Congenital heart malformation, truncus arteriosus.


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


• American Heart Association: Congenital Heart Defects & Genetics.