STK11 (LKB1) Gene Mutation Analysis
Peutz-Jeghers syndrome (PJS) is a cancer predisposition syndrome characterized by gastrointestinal polyps and hyperpigmentation of mucocutaneous tissue. Onset of the melanotic macules occurs early in childhood, typically on the lips between the ages of 1 and 5. In some cases, these macules may fade or disappear after puberty. Abdominal complaints generally begin to occur between the ages of 6 and 18, usually as abdominal pain due to intussusception 1. Other less common malignancies associated with PJS are pancreatic, breast, lung, ovary, uterus, cervix, and testicular cancers. The cumulative risk for developing any type of cancer in PJS is 5%, 17%, 31%, 60%, and 85% at ages 30, 40, 50, 60, and 70, respectively 2. Mutations in the STK11 gene have been found to cause PJS. Testing for both small alterations (single base pair changes, small insertions/deletions) and for large multi-exon deletions, affords a detection rate of roughly 75% in individuals without a family history. This approaches 95% in individuals with a positive family history of PJS 3. Approximately one fourth of these mutations are de novo, and they exhibit incomplete penetrance and variable expressivity.
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