individuals.. apc-associated polyposis conditions historically accounted for about 0.5% of all colorectal cancers; this figure is declining as more at-risk family members undergo successful treatment following early polyp detection and prophylactic colectomy.""likely underdiagnosed, given the lower number of colonic polyps and lower risk for colorectal cancer compared to classic fap" ? treatment of manifestationsclassic fap: "colectomy is recommended after adenomas emerge; colectomy may be delayed depending on the size and number of adenomatous polyps. colectomy is usually advised when more than 20 or 30 adenomas or multiple adenomas with advanced histology have developed""colectomy may be necessary, but in approximately one third of individuals the colonic polyps are limited enough in number that surveillance with periodic colonoscopic polypectomy is sufficient" ? surveillance (monitoring) activities once risk is established"sigmoidoscopy or colonoscopy every 1–2 years, beginning at age ten to 12 years; colonoscopy, once polyps are detected; annual colonoscopy, if colectomy is delayed more than a year after polyps emerge (age ten to 20 years with certain milder symptoms, delay in colectomy may be considered); esophagogastroduodenoscopy (egd) by age 25 years or prior to colectomy and repeated every 1–3 years; in some cases, endoscopic retrograde cholangiopancreatography (ercp) to evaluate for adenomas of the common bile duct; small-bowel imaging when duodenal adenomas are detected or prior to colectomy, repeated every 1–3 years depending on findings; screening for hepatoblastoma (optimal interval unknown, one paper recommends "at least every three months"); annual physical examination, including evaluation for extraintestinal manifestations, and palpation of the thyroid with consideration of follow-up ultrasound examination and fine-needle aspiration if thyroid nodules are present""colonoscopy every two to three years, beginning at age 18 to 20 years; esophagogastroduodenoscopy (egd) beginning by age 25 years or prior to colectomy and repeated every 1–3 years; in some cases, endoscopic retrograde cholangiopancreatography (ercp) may be necessary to evaluate for adenomas of the common bile duct; annual physical examination with palpation of the thyroid with consideration of follow-up ultrasound examination and fine-needle aspiration if thyroid nodules are present. colectomy usually advised when more than 20 or 30 adenomas or multiple adenomas with advanced histology have developed." sovaria states as at 1998 that "colonoscopy, as opposed to sigmoidoscopy, should be advised for endoscopic surveillance, because of the right-side location of colorectal adenomas; ugi endoscopic surveillance is warranted in an attempt to detect premalignant gastric or duodenal tumors; individuals affected with may require total colectomy with ileo-rectal anastomosis only when prophylactic colectomy is advised" ? decision to monitor"early recognition may allow for timely intervention and improved final outcome; thus, surveillance of asymptomatic, at-risk children for early manifestations is appropriate; genetic testing is more cost effective than sigmoidoscopy in determining who in the family is affected; individuals diagnosed with apc-associated polyposis conditions as a result of having an affected relative have a significantly greater life expectancy than those individuals diagnosed on the basis of symptoms.. as colon monitoring for those at risk for classic fap begins as early as age ten to 12 years, molecular genetic testing is generally offered to children at risk for classic fap by age ten years. genetic testing at birth may also be warranted, as some parents and pediatricians may consider hepatoblastoma screening from infancy to age five years in affected offspring.. no evidence points to an optimal age at which to begin screening."see fap. also "colon screening for those with attenuated fap begins at age 18 to 20 years; thus, molecular genetic testing should be offered to those at risk for attenuated fap at approximately age 18 years." ? inheritance and implications of confirmed diagnosis for other close relativesapc-associated polyposis conditions are inherited in an autosomal dominant manner. approximately 20–25% have the altered gene as the result of a de novo gene mutation. little or no evidence of maternal/paternal bias, or effect related to advanced paternal age, in de novo mutations. siblings have classic 50% risk of sharing the condition if inherited and not de novo and a "low" but slightly higher risk than general if de novo, therefore genetic testing should be offered. offspring each have a 50% chance of inheritance. other family members are at risk if their parents share the same mutation. germline mosaicism has been documented in asymptomatic cases. prenatal testing is possible via fetal extracted dna.see fap ? polyposis registries because of the genetic nature of fap, polyposis registries have been developed around the world. the purpose of these registries is to increase knowledge about the transmissibility of fap, but also to document, track, and notify family members of affected individuals. one study has shown that the use of a registry to notify family members (call-ups) significantly reduced mortality when compared with probands. the st. mark's polyposis registry is the oldest in the world, started in 1924, and many other polyposis registries now exist.