[Genetic analysis of a Chinese pedigree affected with Cowden syndrome due to variant of PTEN gene].

Objective: To explore the clinical features and genetic etiology of a Chinese pedigree affected with Cowden syndrome (CS).

Methods: A CS pedigree diagnosed in November 2022 at the Ningde Municipal Hospital Affiliated to Ningde Normal University was selected as the study subject. Clinical data were collected, and genetic testing was carried out for available members. Pathogenicity analysis was carried out for the candidate variant.

Results: The proband, a 7-year-old male, was found to have autism and intellectual disability. Whole exome sequencing revealed that he has harbored a c.462_463del (p.F154Lfs25) variant of the PTEN gene. The proband's 35-year-old mother, who was diagnosed with pulmonary hamartomas at our hospital, has manifested with lipomas, nodular goiter, and adenomas. Sanger sequencing confirmed that she was also heterozygous for the c.462_463del (p.F154Lfs25) variant of the PTEN gene. No other family members has carried the same variant. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as pathogenic (PVS1+PM2_Supporting+PM6).

Conclusion: The newly discovered c.462_463del (p.F154Lfs*25) variant of the PTEN gene probably underlay the CS in this pedigree. CS patients have higher risk for developing malignant tumors. Clinicians should be aware of this condition and emphasize follow-up of the patients.