Familial Adenomatous Polyposis Disease Research Articles

Surgical Decision-Making in Familial Adenomatous Polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder affecting patients with germline mutations of the adenomatous polyposis coli (APC) tumor suppressor gene. The surgical treatment of colorectal disease in FAP, which has the goal of colorectal cancer prevention, varies based on both patient and disease factors but can include the following: total colectomy with ileorectal anastomosis, proctocolectomy with stapled or hand-sewn ileal pouch-anal anastomosis, or total proctocolectomy with end ileostomy. The operative options and extent of resection, as well as the use of endoscopy and chemoprevention for the management of polyposis, will be discussed in detail in this article. In addition, commonly debated management decisions related to the treatment of patients with FAP, including the timing of prophylactic colorectal resections for patients with FAP and management of the polyp burden in the rectum, will be discussed. Finally, genotype considerations and the impact of desmoid disease on operative decisions in the setting of FAP will also be reviewed.

Molecular Study of Nucleotide Changes of ATPase6 and MT-CYB Genes in the Mitochondrial Genome of Patients with Familial Adenomatous Polyposis (FAP)

Introduction: Familial adenomatous polyposis (FAP) is a rare and hereditary disease in which multiple precancerous polyps develop in the patient's colon. Familial adenomatous polyposis is caused by mutations in the APC gene (5q21). According to new research, in addition to nuclear disorders, mitochondrial functional disorders are also one of the essential carcinogenic factors and also a promising target for cancer treatment. The aim of this study was to investigate the nucleotide changes of mitochondrial ATPase6 and MT-CYB genes in patients with FAP.
 Methods: In this study, 9 Iranian families with Familial adenomatous polyposis were investigated to study mutations in mitochondrial genes. For this purpose, a fragment with the length of 558bp containing the ATPase6 gene and also a fragment containing the MT-CYB gene with a length of 853bp were studied using the Touchdown-PCR method and sequencing. Sequencing results were analyzed with several bioinformatics software and databases, including ExPASy, SIFT, PSIPRED, PolyPhen-2, I-Mutant, PROVEAN, PredictSNP, and PyMol.
 Results: In this research, five mutations were observed in the mitochondrial ATPase6 gene. Three mutations were synonymous (c.A8901G; p.L125L, c.C8958T; p.I144I and c.C8943T; p.P139P) and two non-synonymous mutations (c.T8780C; p.L85P and c.G9133A; p.E203K). Furthermore, two synonymous mutations (c.A15607G; p.K287K and c.C15833T; p.L363L) and one non-synonymous mutation (c.C15452A; p.L236I) were observed in the MT-CYB gene.
 Conclusion: In this study, ATPase6 and MT-CYB genes were investigated in the patients with Familial adenomatous polyposis, and 5 and 3 mutations and nucleotide changes were observed in affected patients, respectively. Considering that mitochondrial genome mutations can play a role in tumorigenesis, identifying new mutations can be effective in early cancer diagnosis. More studies are needed to confirm the association between mitochondrial mutations and FAP disease.

An update of the variant spectrum of the APC gene in Iranian familial adenomatous polyposis patients

Familial adenomatous polyposis (FAP) is an autosomal dominant colorectal cancer syndrome that is characterized by the development of multiple adenomas in the colon and rectum with high penetrance rates. This disease has specific features like the occurrence of pathogenic variations in the APC gene and diverse FAP phenotypes due to the occurrence region. In this study we aimed to evaluate pathogenic variants in exons of the APC gene in Iranian patients with FAP. A total of 35 FAP individuals were referred to the gastroenterology ward of Taleghani Hospital. As the aim of the study was to study the germline variations in the participants, the peripheral blood was collected and after the DNA extraction, PCR, and Sanger sequencing processes for the APC gene, the results were evaluated by the ACMG classification guidelines to report their pathogenicity. Accordingly, out of eight specific detected variants, three of them were novel, and the rest were reported previously. These eight variants were all truncating protein and pathogenic, and they were limited to 849–1378 codons. Overall, detected variants revealed discrepancies and parallels with previous reported cases in terms of quantity, occurrence region, and association with demographic and clinicopathological characteristics of patients. The spectrum of detected variants and the patient’s phenotype showed distinct characteristics, such as occurrence in specific regions and the absence of extracolonic symptoms like Congenital hypertrophy of the retinal pigment epithelium (CHRPE). These findings open the path to comprehending the typical symptoms, their rarity, and their occurrence in the Iranian population and also due to the facts, we found that the studying of the APC gene alone for diagnosing FAP disease is not sufficient, and considering other genes are completely rational in the case of sequencing and studying the variants.

APC mutational patterns in gastric adenocarcinoma are enriched for missense variants with associated decreased survival.

Adenomatous polyposis coli (APC) mutations are causally associated with familial adenomatous polyposis (FAP) and are recurrent somatic events across numerous tumor types, including gastric adenocarcinoma. Severity of disease in FAP correlates with specific APC mutations, but the impact of given mutations on phenotype in gastric cancer is not well studied. Sequencing data from the Genomic Data Commons (GDC) demonstrate an APC mutational pattern in gastric cancer that differs dramatically from that seen in colon cancer. Exome sequencing data from APC-mutant colon and gastric adenocarcinomas in GDC was filtered for single nucleotide variants (SNVs) using MuTect2 Variant Aggregation and Masking pipeline, Somatic Aggregation Workflow. APC mutations were found in 57/441 gastric (12.9%) and 309/433 colon adenocarcinomas (71.4%). There was a significant difference in the proportion of stopgain, frameshift, and missense mutations between tumor types(P < .00001). Colon tumors were predominated by frameshift and stopgains, comprising 47.7% and 35.7%, respectively. In contrast, 47.1% of gastric mutations were missense. Gastric tumors harboring missense mutations showed decreased overall survival relative to other mutational subtypes(P = .008). In the gastric samples, 25.9% of frameshift and stopgain mutations are in the 3' portion of the gene, compared to 1.4% of colon samples. APC mutations demonstrate different distributions in gastric and colon adenocarcinoma, with a shift toward missense variants in gastric tumors and worse survival in gastric tumors harboring them. As different mutations confer variable degrees of protein dysfunction and resultant clinical manifestation, expanded investigation of specific mutational patterns will prove integral to future-risk stratification strategies.

Congenital Hypertrophy of Retinal Pigment Epithelium for Diagnosis of Familial Adenomatous Polyposis - the First FAP registry in Iran

Objective:Familial adenomatous polyposis (FAP), an autosomal dominant inherited disorder is characterized by the presence of multiple adenomatous colorectal polyps, which can develop into cancer during early adulthood. Therefore, early diagnosis is essential. Most FAP patients have several extracolonic manifestations, including congenital hypertrophy of the retinal pigment epithelium (CHRPE). Whereas genetic markers may provide the main route to detection of “at risk” subjects , at present this approach is clearly limited and searches for a noninvasive phenotypic marker continue to be high priority. The aim of this study was to describe the pattern of distribution of CHRPE lesions and evaluate their diagnostic value in FAP patients and their family members in a local population.Methods:A total of 23 FAP patients and 26 relatives belonging to 12 families at high risk of developing FAP were subjected to colonoscopic and ophthalmological examination.Result:Retinal examinations demonstrated prevalences of CHRPE in FAP patents and their siblings of 78% and 38%, respectively. We were able to illustrate a significant correlation between FAP disease and the presence of retinal lesions. Sensitivity and specificity of CHRPE as a screening test to detect the presence of FAP are 78.3% and 61.5%, respectively, with a positive predictive value of 64.3% and a negative predictive value of 76.2 %. A “lesion form” significant difference was found between FAP and normal participants. Spearman nonparametric analysis revealed no correlation between age and number or size of lesions.Conclusion:Multiple CHRPE lesions are a diagnostic feature of FAP patients They are specific and sensitive clinical markers of this disease (specificity 60% and sensitivity 77%).

The importance of a large sample cohort for studies on modifier genes influencing disease severity in FAP patients

BackgroundFamilial adenomatous polyposis (FAP) is usually characterised by the appearance of hundreds-to-thousands of adenomas throughout the colon and rectum and if left untreated the condition will develop into CRC with close to 100% penetrance. Germline mutations in the APC gene, which plays an integral role in the Wnt-signalling pathway, have been found to be responsible for 70-90% of FAP cases. Several studies suggest that modifier genes may play an important role in the development of CRC and possible modifiers for FAP have been suggested. Interestingly, a study has found that SNPs within ATP5A1 is associated with raised levels of ATP5A1 expression and high expression levels may facilitate CRC development. We aimed to determine if SNPs in ATP5A1 modify the risk of developing CRC/adenomas in FAP patients.MethodsGenomic DNA from 139 Australian FAP patients with a germline APC mutation underwent genotyping at the Australian Genome Research Facility (AGRF) utilising iPLEX GOLD chemistry with Sequenom MassArray on an Autoflex Spectrometer for 16 SNPs in the ATP5A1 gene. Association between ages of diagnosis/risk of CRC/adenomas was tested with Kaplan-Meier estimator analysis, logistic regression and cox proportional hazard regression.ResultsAn association between age of diagnosis of CRC and genotypes was observed for SNP rs2578189 (p = 0.0014), with individuals harbouring the variant genotype developing CRC 29 years earlier than individuals harbouring the wildtype genotype. Individuals harbouring the variant genotype of SNP rs2578189 were also at increased risk of CRC (HR = 13.79, 95% CI = 2.36-80.64, p = 0.004). We used an independent Dutch FAP cohort (n = 427) to validate our results; no association between SNP rs2578189 and CRC was observed.ConclusionThese results highlight the difficulties in studying a disease that has a high degree of intervention and also emphasize the importance of large sample sizes when searching for modifier genes in patients with an inherited predisposition to disease. To fully determine if there are genetic modifiers of disease in FAP we would encourage people that are interested in collaborating in future studies into the role of modifier genes in disease expression in FAP to join forces.

Advanced duodenal disease in familial adenomatous polyposis: how frequently should patients be followed up after successful therapy?

Duodenal polyposis is found in the majority of patients with familial adenomatous polyposis. Endoscopic surveillance programmes grade the severity of duodenal disease according to the Spigelman classification (stages 0-IV) to identify patients at risk of developing adenocarcinoma. To evaluate the progression of duodenal polyposis in patients with a previous diagnosis of Spigelman stage IV disease who have been downstaged by endoscopic or pharmacological means. A database search of a large polyposis registry identified patients who had been downstaged from stage IV disease and had further opportunity for disease progression. These patients were divided into three groups according to their new Spigelman stage. A measure of a patient's disease progression was obtained by the increase in stage over the recommended follow up time period for their new, reduced, Spigelman stage. Group 1 (n=16) were downstaged to stage III disease, with 50% progressing back to stage IV over the recommended 1-year follow up period. Group 2 (n=19) were downstaged to stage II disease, with 84% progressing over the recommended 3-year follow up period. Group 3 (n=6) were downstaged to stage I disease, with 100% progressing over the recommended 5-year follow up period. Patients downstaged from Spigelman stage IV demonstrate an increased rate of disease progression in comparison to reported rates of primary disease progression. An amendment to the current endoscopic surveillance protocol is recommended to ensure that once a patient has been diagnosed with stage IV disease they are treated as a high-risk patient in perpetuity.

Gene variants associated to malignant thyroid disease in familial adenomatous polyposis: A novel APC germline mutation

Familial adenomatous polyposis (FAP) is an autosomal inherited syndrome characterized by hundreds to thousands colorectal adenomatous polyps with oncological transformation lifetime risk of 100%. FAP is mainly associated with mutations in APC (autosomal dominant inheritance) or MUTYH (autosomal recessive inheritance) genes. Affected individuals are at increased risk of developing extra-intestinal tumors. Lifetime risk of developing thyroid carcinoma has been described in previous reports of about 2-12%, mainly in females, and the mean age is below 30 yr. About 95% of cancers are papillary thyroid carcinomas (PTC), mostly multifocal. The aim of this study was to evaluate the frequency of PTC among our series of FAP patients and to assess the type of gene mutation associated with the disease. Fifty-four subjects from 36 FAP families were selected (29 females/25 males) and the mean age (±SD) at diagnosis was 28.8±10.8 yr. All patients underwent blood examination for thyroid hormones and antibodies, germline mutational analysis of APC and/or MUTYH genes, thyroid ultrasound, and endocrinological evaluation. In 13/54 (24.1%) subjects, an eumetabolic thyroid disease was found: plurinodular disease in 7/54 (13.0%); single nodule in 4/54 (7.4%); in 2/54 patients (3.7%), we found a malignant nodule characterized after total thyroidectomy as a classical PTC. Both patients were female and showed a classic FAP phenotype. Mutational analysis revealed in the first patient the APC germline mutation 3183_87del ACAAA and in the second patient the del9-10 (del9080dup11) novel APC variant; the first mutation has been already reported in association with PTC; to our knowledge the second mutation has never been previously reported in association with FAP. In the population examined, the estimated prevalence of thyroid malignant diseases was 3.7%. In both patients, the identified APC gene pathogenetic variants mapped within the 5' region of the gene, previously reported as a PTC-associated mutational hot spot. Both patients had classic FAP phenotype and genetic analysis revealed two pathogenetic APC mutations: c.3183_87delACAAA, a recurrent pathogenetic variant and del9-10 (del9080dup11), a novel, not previously described genomic rearrangement. In agreement with previous studies, the morpho-functional surveillance of thyroid in FAP series should be recommended. A better insight into the overall genotype-phenotype correlation of APC gene mutations would be helpful for the identification of at-risk individuals.

Preclinical studies of gene transfer for the treatment of desmoid disease in familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) arises following mutation or loss of the adenomatous polyposis coli (APC) gene. Desmoid tumours are proliferations of fibroblasts and occur as an extracolonic manifestation of FAP. They are a leading cause of death after colectomy. The aim of this study was to assess the potential for APC gene transfer into fibroblasts in vitro and in vivo as a basis for consideration of gene therapy in the prevention or treatment of desmoid tumours. The APC gene was transferred by lipofection into fibroblasts in tissue culture and into peritoneum and small bowel mesentery in vivo. Reverse transcriptase-polymerase chain reaction was used to determine whether or not transfection was successful. Transgene expression was recorded in vitro to 7 days after transfection. High levels of transgene expression were also seen in samples of peritoneum (all eight mice), small bowel mesentery (seven of eight), liver (seven of eight) and intestinal tissues (five to six of eight) following intraperitoneal treatment. Interestingly, transgene expression in gonadal tissues was occasionally noted. Liposomal transfection of APC gave prolonged high-level expression of the transgene, an important basis for gene therapy. No adverse effects were recorded. Further work is needed in animal models of desmoid disease to assess the clinical effects of gene therapy.

Variability in the severity of colonic disease in familial adenomatous polyposis results from differences in tumour initiation rather than progression and depends relatively little on patient age

INTRODUCTIONAs large scale genetic analysis becomes increasingly efficient, attention is turning to problems arising from inaccurate measurement of the phenotype. We have investigated the underlying basis of variation in disease...