FLAT POLYPOSIS, ATTENUATED POLYPOSIS - MO LECULAR DIAGNOSIS

In typical colonic polyposis, huge numbers of polyps develop at an ear ly age, whereas in milder forms age at onset is older and the number o f polyps does not exceed 100. Molecular studies have shown that the ge rminal mutations seen in typical polyposis are located all along the A PC genes and result either in loss of the APC proteins encoded by the mutated gene or in production of truncated proteins. The mutations in milder forms (exons 3 and 4, exon 9) may allow continued production of the APC proteins encoded by the alternate short transcripts of the AP C gene, ensuring preservation of part of the cellular functions of the APC proteins.