Germline PTEN mutations are rare and highly penetrant

Area of Science:

• Genetics
• Oncology
• Medical Diagnostics

Background:

• Cowden syndrome, also known as multiple hamartoma syndrome, is an early-onset genetic disorder.
• It is characterized by multiple hamartomas and an increased risk of developing breast, thyroid, and endometrial cancers.
• Germline mutations in the PTEN gene have been identified as the cause of Cowden syndrome.

Purpose of the Study:

• To evaluate the diagnostic utility of PTEN mutation testing in families with Cowden syndrome or suspected Cowden syndrome.
• To confirm the association between PTEN mutations and clinical diagnosis of Cowden syndrome in a Norwegian cohort.
• To provide age-related penetrance data for neoplasms associated with Cowden syndrome.

Main Methods:

• Diagnostic and predictive genetic testing for PTEN mutations was performed.
• Families were categorized based on clinical criteria for Cowden syndrome and cancer history.
• Testing included families registered at Norwegian cancer family clinics.

Main Results:

• PTEN mutations were identified in all six families meeting the clinical criteria for Cowden syndrome.
• No PTEN mutations were found in families not meeting the criteria or in families with a history of breast and thyroid cancers alone.
• De novo mutations were observed in most families.

Conclusions:

• Germline PTEN mutations are causative in Cowden syndrome.
• PTEN genetic testing is a reliable diagnostic tool for Cowden syndrome.
• The study provides valuable data on the genetic basis and clinical presentation of Cowden syndrome.