Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 34-2003. A 45-year-old woman with a family history of colonic polyps and cancer

Pathogenic APC Variants in Latvian Familial Adenomatous Polyposis Patients

Background and objectives: Familial adenomatous polyposis is one of the APC-associated polyposis conditions described as genetically predetermined colorectal polyposis syndrome with a variety of symptoms. The purpose of this study was to determine sequence variants of the APC gene in patients with familial adenomatous polyposis (FAP) phenotype and positive or negative family history. Materials and Methods: Eight families with defined criteria of adenomatous polyposis underwent molecular genetic testing. Coding regions and flanking intron regions of the APC gene were analyzed by Sanger sequencing. Results: Eight allelic variants of the APC gene coding sequence were detected. All allelic variants of the APC gene were predicted to be pathogenic based on criteria according to the “Joint Consensus Recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology” (2015), four of them c.1586_1587insAT, c.2336delT, c.3066_3067insGA, and c.4303_4304insC, were considered novel. Conclusions: The timely molecular genetic analysis of APC germline variants and standardized interpretation of the pathogenicity of novel allelic variants has a high impact on choice for treatment, cancer prevention, and family genetic counseling.

[Long-term experience with therapy of a female patient with Gardner's syndrome, first presenting with extra-abdominal desmoid tumor, and review of the literature]

Gardner's syndrome is a clinical subgroup of familial adenomatous polyposis, an autosomal dominant disease. It is characterized by gastrointestinal polyps and extra-intestinal manifestations including multiple osteomas, skin and soft tissue tumours. Aggressive desmoid tumours can be very difficult to manage in patients with Gardner's syndrome. We present a case of a 17-year-old female who presented with an aggressive desmoid tumor arising of the lumbar area as part of her Gardner's syndrome. She was treated with surgery, nonsteroidal anti-inflammatory drugs, tamoxifen and radiotherapy, and was followed up for 80 months. We conclude that desmoid tumors can precede gastrointestinal manifestations of familial adenomatous polyposis or Gardner's syndrome. Such patients should be evaluated with genetic testing followed by colonoscopy. Desmoid tumours should be managed in a multidisciplinary setting, as well.

Nine-year follow-up of a patient with attenuated familial adenomatous polyposis treated with cyclo-oxygenase-2 inhibitors

Familial adenomatous polyposis (FAP) is caused by germline mutations in the adenomatous polyposis coli (APC) gene with onset of florid polyposis in childhood and development of colorectal cancer by age 30. Colectomy is advised because of the high risk of developing colorectal cancer. Attenuated FAP (AFAP) is a variant of this condition with a later age of onset and milder clinical phenotype; however, colectomy is advised once polyposis develops and polyps cannot be managed endoscopically. We report a case of a patient with AFAP and previously resected colonic carcinoma that was treated with chemoprophylaxis with long-term cyclooxygenase-2 (COX-2) inhibitors after declining colectomy. Colonoscopic examination demonstrated regression of polyps by 18 months. After 9 years of follow-up, there was no evidence of colorectal cancer development or progression of polyposis. This is the first case report on long-term treatment with COX-2 inhibition in a patient with AFAP and previous colonic carcinoma.

Oral and maxillofacial manifestations of familial adenomatous polyposis

Patients with familial adenomatous polyposis (FAP) develop multiple premalignant colorectal adenomas. Untreated, one or more of these polyps will progress to colorectal carcinoma in middle-aged adults. Extra-intestinal manifestations of FAP are frequently observed and this combination has been called Gardner's syndrome. Oral and maxillofacial symptoms of FAP include an increased risk of jaw osteomas, odontomas and supernumerary or unerupted teeth. Early diagnosis of FAP is crucial and may be life saving. As oral signs usually precede gastrointestinal symptoms, the dentist may play an important role in the diagnosis of FAP.

Modalities of gene action predicted by the classical evolutionary biological theory of aging

What might now be referred to as the "classical" evolutionary biological theory of why we age has had a number of serious challenges in recent years. While the theory might therefore have to be modified under certain circumstances, in the author's opinion, it still provides the soundest theoretical basis for thinking about how we age. Nine modalities of gene action that have the potential to modulate processes of aging are reviewed, including the two most widely reviewed and accepted concepts ("antagonistic pleiotropy" and "mutation accumulation"). While several of these nine mechanisms can be regarded as derivatives of the antagonistic pleiotropic concept, they frame more specific questions for future research. Such research should pursue what appears to be the dominant factor in the determination of intraspecific variations in longevity-stochastic mechanisms, most likely based upon epigenetics. This contrasts with the dominant factor in the determination of interspecific variations in longevity-the constitutional genome, most likely based upon variations in regulatory loci.

Hereditary colorectal cancer syndromes: an overview

Approximately 5% of the 140,000 cases of colorectal cancer diagnosed annually are attributable to an underlying hereditary colorectal cancer syndrome. However, this is likely to be an underestimation. Our understanding of the genetic basis, as well as the guidelines for clinical management of these syndromes, continue to evolve rapidly. Because of the high risk of not only colorectal cancer but also multiple extracolonic tumors, it is crucial for clinicians to recognize the unique features in the diagnosis and management of these high-penetrance syndromes, including familial adenomatous polyposis, MYH-associated polyposis, and hereditary nonpolyposis colon cancer.

Variation of a variation: case report of attenuated familial adenomatous polyposis

BACKGROUND

First described in 1988, attenuated familial adenomatous polyposis (AFAP) is a rare autosomal dominant precancerous condition of the gastrointestinal tract. Few reports have described adenocarcinomatous change in the gastroduodenal region thus far.

CASE OUTLINE

We report a case of AFAP presenting with extensive gastric polyposis and ampullary adenocarcinoma in absence of a positive family history of gastrointestinal cancer and a novel mutation.

Genetics of hereditary colorectal cancer

Genetic factors can dramatically influence the risk of colorectal cancer, and the molecular bases of many hereditary colorectal cancer syndromes, including familial adenomatous polyposis (FAP), attenuated FAP (AFAP), and hereditary nonpolyposis colorectal cancer (HNPCC) have been elucidated. Additional syndromes continue to be defined as new genes, including MYH , are linked to the development of colonic polyps and cancer. The risks of colorectal cancer are variable and depend on the specific germline alterations. Some mutations are associated with a 100% lifetime risk of developing cancer, while others are associated with only a mild increase in risk. Although there are overlapping clinical features in many of these syndromes, they can be distinguished by the age at cancer diagnosis, inheritance pattern, number and distribution of polyps, specific histologic features of the cancers, and the presence of distinctive extracolonic features. The introduction and refinement of genetic testing has provided a new and invaluable tool for the diagnosis and assessment of cancer risk for suspected cases of hereditary colon cancer.