Current status of the genetic susceptibility in attenuated adenomatous polyposis

Adenomatous polyposis(AP)is classified according to cumulative adenoma number in classical AP(CAP)and attenuated AP(AAP).Genetic susceptibility is the major risk factor in CAP due to mutations in the known high predisposition genes APC and MUTYH.However,the contribution of genetic susceptibility to AAP is lower and less understood.New predisposition genes have been recently proposed,and some of them have been validated,but their scarcity hinders accurate risk estimations and prevalence calculations.AAP is a heterogeneous condition in terms of severity,clinical features and heritability.Therefore,clinicians do not have strong discriminating criteria for the recommendation of the genetic study of known predisposition genes,and the detection rate is low.Elucidation and knowledge of new AAP high predisposition genes are of great importance to offer accurate genetic counseling to the patient and family members.This review aims to update the genetic knowledge of AAP,and to expound the difficulties involved in the genetic analysis of a highly heterogeneous condition such as AAP.

APC蛋白表达在衰减型家族性腺瘤性息肉病诊断中意义的初步探讨

目的初步探讨APC蛋白表达在衰减型家族性腺瘤性息肉病诊断中的意义。方法疑似衰减型家族性腺瘤性息肉病67例,散发性大肠腺癌30例,正常大肠粘膜30例作为正常对照。采用免疫组化法检测各组中APC蛋白表达水平。结果疑似衰减型家族性腺瘤性息肉病组APC蛋白阴性表达率26.87%(18/67),其中10枚≤结肠腺瘤数目<100枚者11例,2枚≤结肠腺瘤数目<10枚并伴发胃底腺息肉或十二指肠腺瘤者7例;散发性大肠腺癌组中APC蛋白阴性表达率为43.33%(13/30);正常大肠粘膜组未发现一例APC蛋白阴性表达。结论伴发胃底腺息肉或十二指肠腺瘤的2枚≤结肠腺瘤数目<100枚且APC蛋白表达阴性者可以诊断为AFAP。不伴胃底腺息肉或十二指肠腺瘤的10枚≤结肠腺瘤数目<100枚者,APC蛋白表达阴性只能作为AFAP的辅助诊断,应调查其家族史,排除APC基因体细胞突变情况。APC蛋白阳性表达的患者不能除外AFAP的可能。