Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033036 (APC)
 10,214 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The management of patients with multiple intestinal polyps may be difficult and greatly depends on the correct classification. Polyposis syndromes account for less than 1% of newly diagnosed colorectal cancers. In addition the risk for extracolonic cancer is increased in most syndromes. Here we report the case of a difficult patient with severe gastric polyposis and we present a review of polyposis syndromes such as classical and attenuated familial adenomatous polyposis (FAP), MYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis as well as rare polyposis syndromes. The most practical approach for the diagnostic workup in patients with newly diagnosed gastrointestinal polyposis is based on the histological typing of polyps. In addition, a detailed family history regarding cancer, polyps and congenital abnormalities should be obtained from every polyposis patient. Patients with multiple adenomas are most likely to suffer from FAP, AFAP or MAP. Of these, younger age and higher polyp count are most likely a diagnosis of typical FAP. Older age and fewer polyps favour a diagnosis of AFAP or MAP. Germline testing of the APC gene is suggested, and if negative, MYH gene testing should be done. In patients with hamartomas, extraintestinal features should be evaluated and reference histology should be initiated. In addition panintestinal imaging should be performed with EGD, colonoscopy and small bowel imaging (PE, CE, and MR) enteroclysis. For diagnostic and therapeutic problems a familial colorectal cancer center should be consulted. Using this algorithm, correct classification and adequate treatment should be possible for every polyposis patient.
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PMID:The patient with multiple intestinal polyps. 1754 8

A large proportion of non-FAP non-HNPCC patients with multiple colorectal adenomas have been reported to carry germline mutations on the MYH gene. Although the number of adenomas appears to be dependent on the number of mutated MYH alleles present in a patient, little is known on the relation of this number with cancer risk. Four hundred fifty-three APC-negative patients with more than five colorectal adenomas were screened for mutations on the entire coding sequence of the MYH gene. Pathogenic mutations were initially found in 74 patients without extradigestive tumors (22.5%) and subsequently in 75 at-risk relatives. Polyposis was more severe in cases with biallelic mutations. However, mutation copy number was correlated neither with the age at diagnosis of adenomas or adenocarcinomas, nor with the presence of a family history of colorectal tumors. Heterozygous and homozygous MYH mutation carriers were both at high risk for synchronous cancers (24% in colorectum and 16% in the upper gastrointestinal tract), but did not demonstrate an increased risk for extradigestive tumors. MYH-associated polyposis is a frequent inherited colorectal cancer predisposition with a strong dominance component. From age 25-30, MYH mutation carriers should be proposed an early screening program, which includes endoscopies of the upper digestive tract and the colorectum every 2 years.
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PMID:Similar colorectal cancer risk in patients with monoallelic and biallelic mutations in the MYH gene identified in a population with adenomatous polyposis. 1794 94

Lynch syndrome, familial adenomatous polyposis, and Mut Y homolog (MYH)-associated polyposis are three major known types of inherited colorectal cancer, which accounts for up to 5% of all colon cancer cases. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 and is inherited in an autosomal dominant manner. Familial adenomatous polyposis is manifested as colonic polyposis caused by mutations in the APC gene and is also inherited in an autosomal dominant manner. Finally, MYH-associated polyposis is caused by mutations in the MUTYH gene and is inherited in an autosomal recessive manner but may or may not be associated with polyps. There are variants of both familial adenomatous polyposis (Gardner syndrome--with extracolonic features--and Turcot syndrome, which features medulloblastoma) and Lynch syndrome (Muir-Torre syndrome features sebaceous skin carcinomas, and Turcot syndrome features glioblastomas). Although a clinical diagnosis of familial adenomatous polyposis can be made using colonoscopy, genetic testing is needed to inform at-risk relatives. Because of the overlapping phenotypes between attenuated familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome, genetic testing is needed to distinguish among these conditions. This distinction is important, especially for women with Lynch syndrome, who are at increased risk for gynecological cancers. Clinical testing for these genes has progressed rapidly in the past few years with advances in technologies and the lower cost of reagents, especially for sequencing. To assist clinical laboratories in developing and validating testing for this group of inherited colorectal cancers, the American College of Medical Genetics and Genomics has developed the following technical standards and guidelines. An algorithm for testing is also proposed.
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PMID:ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis). 2431 Mar 8


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