Familial Adenomatous Polyposis （FAP） had been thought to be an autosomal dominant inheritance disorder. But, recently researchers indicate that some FAP-patients have an autosomal recessive inheritance manner due to biallelic alterations of MYH gene. This finding have increased the significance of a genetic diagnosis in genetic counseling for FAP. Especially, identification of genetic mutations in FAP-patients without family history is so important to clarify the inheritance mode. A conventional DNA direct sequencing method could not detect pathogenic mutations of patients in approximately 20% of actual FAP-families. A novel technique, multiplex ligation-dependent probe amplification （MLPA）, will be expected contribution for the improvement of the detection rate, and will have highly clinical utility.
Familial adenomatous polyposis（FAP） is a hereditary syndrome to show autosomal dominant inheritance, and causative gene is APC gene. Subjects with FAP constitute a very high risk group for colorectal cancer and lifetime risk of colorectal cancer goes over 95% throughout the life. Genotype-phenotype correlations between APC gene and FAP have been elucidated gradually. We examined the mutation of APC gene in 45 FAP kindred that were registered with Tohoku Familial Tumor Association.
We are systematically collecting the family histories of cancer patients upon admission. Members of the familial tumor counseling service select patients with familial tumors to receive genetic counseling. An attitude survey was conducted among the general public and medical doctors concerning the collecting of family histories. As a result of analysis of the questionnaires set up in a web page for the general public some people felt an interrogative and disagreeable sensation when they were asked about their family history. Most people wanted to undergo genetic testing for cancer, or wanted to do it depending on the terms of testing. If a genetic test was positive, many people answered that they would inform their spouses, parents, and friends of the test results, but this tendency was weak for their parents-in-law or grandparents. The result of questionnaires administered to medical doctors showed that a small number of patients refused to complete the survey about the family history and a small number of doctors had felt a sense of guilt when surveying for the family history. This is a small pilot survey and does not necessarily represent the general population. A more discreet analysis is therefore required.