[Clinical and genetic features of APC- and MYH-mutation-negative patients with multiple polyposis of large bowel that...

The genealogic analysis, molecular and clinical investigations has been carried out in 19 probands with multiple colorectal adenomas (approximately 100 or more). Twelve of these patients (63.1%) were APC and MYH mutation-negative. Three (25%) probands have positive family history. The median of the disease manifestation age in APC-negative patients was intermediate between the median of the disease manifestation age in APC- and MYH-positive patients. Extraintestinal manifestations in the APC-negative probands are more rare than in APC-positive patients. A half of APC- and MYH-negative probands with multiple polyposis had colorectal cancer. APC- and MYH-negative patients formed a genetically heterogenous group.