Peutz-Jeghers syndrome Peutz-Jeghers syndrome is a genetic autosomal dominant condition leading to gastrointestinal polyps, which predisposes to the development of gastrointestinal, pancreatic, breast, uterine among other malignancies. Diagnostic and predictive genetic testing is now possible thanks to identification of causative mutations in the serine/threonine kinase (STK)-11 (also known as the LKB1) gene.