Is Familial Adenomatous Polyposis hereditary?

Familial Adenomatous Polyposis is a hereditary condition caused by a germline mutation in the APC gene, meaning it is passed down through families in an autosomal dominant pattern. Because it is a genetic disorder, every child of an affected parent has a 50% chance of inheriting the mutation and developing the condition.

Is Familial Adenomatous Polyposis hereditary?

Yes, Familial Adenomatous Polyposis (FAP) is strictly hereditary. It follows an autosomal dominant inheritance pattern, which means only one copy of the altered APC gene is required to cause the disease. While most cases are inherited from a parent, approximately 20% to 25% of individuals with Familial Adenomatous Polyposis have no family history, resulting from a de novo (spontaneous) mutation that occurred for the first time in that individual.

How is genetic testing utilized for Familial Adenomatous Polyposis?

Genetic testing for Familial Adenomatous Polyposis is the gold standard for confirming a clinical diagnosis and identifying at-risk relatives. If a specific APC mutation is identified in a family, targeted testing can be offered to asymptomatic relatives to determine if they carry the mutation. Key aspects of genetic management include:

• Predictive Testing: Recommended for children of affected parents, typically starting in late childhood (around age 10-12), to guide the timing of colonoscopic surveillance.


• Genetic Counseling: Essential for discussing the implications of a positive result, potential for prophylactic surgery, and family planning.


• Prenatal Options: Families may explore options such as Preimplantation Genetic Testing (PGT) during IVF to prevent passing the APC mutation to future generations.

What is the role of genetic counseling?

Managing Familial Adenomatous Polyposis is a lifelong journey. Genetic counselors help families navigate the emotional and clinical complexities of the condition, including the high penetrance of colorectal cancer if left untreated. With 147 members currently sharing their experiences on DiseaseMaps.org, you are not alone in managing the implications of this diagnosis.

Next steps

• Consult a board-certified genetic counselor to discuss family screening protocols.


• Speak with a gastroenterologist specializing in hereditary polyposis syndromes.


• Connect with the DiseaseMaps.org community to share experiences with others living with Familial Adenomatous Polyposis.

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

References

• NIH Genetic and Rare Diseases (GARD) Information Center: Familial Adenomatous Polyposis.


• Orphanet: Familial Adenomatous Polyposis (ORPHA733).


• OMIM (Online Mendelian Inheritance in Man): Adenomatous Polyposis of the Colon (Entry #175100).


• The Polyposis Registry and patient advocacy groups.