Peutz-Jeghers Syndrome - STK11

Clinical Features

Peutz-Jeghers Syndrome (PJS) is an autosomal dominant inherited disease marked by the occurrence of characteristic polyps and melanocytic macules of the lips and buccal mucosa. Polyps develop predominantly in the small intestine, but can also occur in the stomach and large intestine. The histology of hamartomatous Peutz-Jeghers polyps is characterised by distinctive, arboreal branching and finely dendritic lamina muscularis mucosae which make it possible to distinguish Peutz-Jeghers from other polyp diseases. The polyps are associated with an increased risk of developing carcinoma; in addition to these typical "Peutz-Jeghers polyps", polyps of another histology (e.g. adenoma) can also occur. There is an increased risk of developing tumor diseases in other tissues (breasts, ovaries, cervix, endometrium, testicles and pancreas).

Perioral pigmentation and pigmentation of the lips and buccal mucosa normally occur in childhood and can diminish in adulthood; there are also patients without melanocytic macules and patients with hyperpigmentation around the eyes.

Genetic Information

The STK11 gene located on chromosome 19 (19q13.3) consists of 9 exons and codes a cytoplasmatic Serin/Threonin kinase 433 amino acids in length and which takes part in the regulation of cell division and differentiation, and signal transduction. In approximately 60% of Peutz-Jeghers patients a mutation in the STK11 gene is detected. In approx. 10-20% of PJS patients, the disease is caused by new mutations. About 90% of family members who have inherited an STK11 gene mutation develop the disease. Half of all patients develop a malignant tumor before the age of 60.