Is Peutz-Jeghers syndrome hereditary?

TL;DR: Peutz-Jeghers syndrome is a hereditary condition caused by a genetic mutation that is passed down through families in an autosomal dominant pattern. This means that an individual with Peutz-Jeghers syndrome has a 50% chance of passing the causative gene mutation to each of their children.

Is Peutz-Jeghers syndrome genetic or hereditary?

Peutz-Jeghers syndrome is both a genetic and a hereditary condition. "Genetic" means the disease is caused by changes (mutations) in the DNA, specifically in the STK11 gene (also known as LKB1) located on chromosome 19. "Hereditary" means that these mutations can be inherited from a parent. In most cases of Peutz-Jeghers syndrome, the condition is passed from an affected parent to their child. However, it is important to note that about 25% of cases occur due to a de novo (spontaneous) mutation, meaning the individual is the first in their family to have the condition, and neither parent carries the mutation.

What is the inheritance pattern of Peutz-Jeghers syndrome?

Peutz-Jeghers syndrome follows an autosomal dominant inheritance pattern. This indicates that only one copy of the altered STK11 gene is sufficient to cause the syndrome. Because the gene is located on an autosome (a non-sex chromosome), males and females are affected with equal frequency. When one parent has Peutz-Jeghers syndrome, the statistical probability for each pregnancy to inherit the mutation is 50%. The clinical presentation can vary significantly even among family members who share the same genetic mutation, a phenomenon known as variable expressivity.

How is genetic testing utilized for families?

Genetic testing for Peutz-Jeghers syndrome is highly recommended to confirm a clinical diagnosis or to clarify risk for relatives. The following steps are standard practice in clinical genetics:

• Diagnostic Testing: Identifying a pathogenic variant in the STK11 gene confirms a diagnosis of Peutz-Jeghers syndrome in symptomatic individuals.


• Predictive Testing: Once a specific familial mutation is identified, at-risk asymptomatic relatives can undergo targeted testing to determine if they also carry the mutation and require increased cancer surveillance.


• Genetic Counseling: Counselors help families understand the 50% risk, discuss the implications for future children, and explain reproductive options.


• Prenatal and Preimplantation Options: For families wishing to avoid passing the condition to offspring, options such as Preimplantation Genetic Testing (PGT) alongside In Vitro Fertilization (IVF) are available to screen embryos for the familial STK11 mutation.

Why is genetic counseling essential for those with Peutz-Jeghers syndrome?

Living with Peutz-Jeghers syndrome involves managing a significantly increased risk of developing gastrointestinal polyps and various cancers throughout one's lifetime. Genetic counseling provides a supportive space to discuss these risks and the importance of early-onset screening protocols. For those currently planning a family, a genetic counselor can provide clarity on the hereditary nature of Peutz-Jeghers syndrome and help navigate the emotional and logistical aspects of family planning, ensuring that parents are fully informed about the risks to their future children.

Next steps

• Consult with a clinical geneticist to discuss genetic testing for the STK11 gene.


• Connect with the 167 members on DiseaseMaps.org who have shared their experiences with Peutz-Jeghers syndrome for peer support.


• Speak with a gastroenterologist or oncologist to establish a surveillance plan based on your genetic status.


• Request a referral to a genetic counselor to discuss family planning and reproductive options.

Medical disclaimer: This information is for educational purposes only and does not constitute medical advice; please consult with a qualified healthcare professional regarding your specific health situation.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Peutz-Jeghers syndrome.


• Online Mendelian Inheritance in Man (OMIM): Entry #175200 (Peutz-Jeghers syndrome).


• Orphanet: Rare disease database entry for Peutz-Jeghers syndrome (ORPHA713).


• The Peutz-Jeghers Syndrome Patient Foundation resources.