The association of specific genetic disturbances with the development of hereditary cancer helps us to understand the risk of suffering from it, the possibility of an earlier diagnosis, and the treatment and prevention of this disease. Familial adenomatous polyposis (FAP) is a pre-neoplastic syndrome characterized by the presence of hundreds of adenomatous polyps in the colon, which develop into a carcinoma. FAP can be diagnosed using sequencing techniques to detect mutations in the germinal line of the APC (adenomatous polyposis coli) gene.The genetic diagnostic approach in families with FAP, previously followed up in the Gastrointestinal Clinic, has both advantages and disadvantages, and places us nearer the disease and patient. Disclosing the results of this genetic test entails relevant problems in clinical practice, which affect the health field and raise legal and ethical issues, along with the familial, occupational, and social implications that knowing the genetic status can have on the patient. Genetic analysis is rare in normal clinical practice, which involves errors in the interpretation of the results obtained, and during the process of genetic counselling. Specialized multidisciplinary units are necessary for the management of patients with FAP undergoing analysis and appropriate genetic counselling, thus providing an individualized service. The creation of FAP registers and protocols for this healthcare process should optimize the management of these patients and their families.

Objective: To evaluate the phenotype and genotype characteristic of patients included in the Andalusian Registry for familial adenomatous polyposis, the genotype/phenotype correlation and the impact of Registry in the frequency of colorectal cancer of registered. Material and methods: A descriptive study of 77 patients with FAP belonging to 33 families, included in a centralized database visited by the physicians of the hospitals taking part in the present study, on prior signing of confidentiality letters. All genetic studies were carried out in the Immunology Service of our institution. Results: We have included in our study 77 patients of 33 families; 31 probands with a mean age of 32 years (13-51) and 46 relatives at risk with a mean age of 21.8 years (6-55). Genetic study informed in 68/77 with positive result in 92.6%. Ten probands showed colorectal cancer (CRC) at the time of diagnosis (32.2%). Only two affected relatives showed CRC at diagnosis (4.3%), a statistically significant difference (p < 0.05). Gastrointestinal involvement was observed in 30/61 (49%), desmoid tumors in 7/77 (9.1%) and congenital hypertrophy of the retinal pigment epithelium in 23/55 (65.7%). 86.7% of patients with this alteration showed mutations between codons 454 and 1019, with a statistically significant correlation ((p< 0.05). Conclusions: The registry has facilitated the genetic diagnosis for all affected families disregard their province of origin. It has also improved the screening of affected relatives and has made it possible to take preventive measures immediately, therefore diminishing the incidence of CRC at diagnosis in registered affected relatives. The correlation between congenital hypertrophy of the retinal pigment epithelium with some mutations is the only phenotypic-genotypic correlation with statistical significance.

INTRODUCCIÓNLa poliposis adenomatosa familiar (PAF) es una enfermedad hereditaria de carácter autosómico dominante, causada por una mutación en la línea germinal del gen APC (gen de la poliposis cólica), situado en el cromosoma 5q21 (1). Clásicamente la PAF se ha caracterizado por la presencia de más de 100 pólipos en el colon y recto, que de forma natural evolucionan indefectiblemente a carcinoma alrededor de la cuarta década de la vida.Para prevenir el desarrollo del cáncer sería necesario extirpar la mucosa del colon y recto en su totalidad. No existe actualmente un proceder único para lograr ese ob- RESUMENObjetivo: analizar la evolución de la mucosa rectal y del reservorio así como idoneidad de los intervalos de seguimiento y del tratamiento realizado para evitar la aparición del cáncer, en una serie de pacientes con poliposis adenomatosa familiar (PAF), intervenidos.Método: estudio prospectivo de 28 pacientes con PAF intervenidos mediante anastomosis íleo-rectal (20 pacientes) y anastomosis íleo-anal con reservorio (8 pacientes). A todos se les había realizado un control endoscópico dos veces al año y análisis del número y características macroscópicas e histológicas de los póli-pos antes y después de la cirugía así como del tratamiento realizado, de sus complicaciones y de la adecuación del intervalo de seguimiento. El seguimiento medio fue de 6,47 años (DE = 4,59; rango = 0,72-16,75 años).Resultados: ninguno de los 26 pacientes que cumplimentaron correctamente el protocolo de seguimiento desarrolló cáncer. Sólo dos pacientes lo desarrollaron al 1,75 y los 3 años, respectivamente del abandono del protocolo. Los pacientes que desarrollaron adenomas durante el seguimiento fueron tratados con éxito mediante polipectomía endoscópica, salvo en dos casos que se indicó cirugía.Conclusiones: en nuestra serie, el incumplimiento de las revisiones ha sido el factor que ha condicionado la aparición de cáncer.Palabras clave: Poliposis adenomatosa familiar. Anastomosis íleo-rectal. Anastomosis íleo-anal con reservorio ileal. Adenomas de colon. Seguimiento posquirúrgico. ABSTRACTObjective: the study was to assess changes in the rectal mucosa and pouch in a series of patients with familial adenomatous polyposis (FAP) who underwent either subtotal colectomy and ileorectal anastomosis (IRA) or proctocolectomy and ileal pouchanal anastomosis (IPAA), and to evaluate the suitability of the follow-up interval and postoperative treatment employed to prevent the development of cancer.Method: this study involved 28 patients with FAP who underwent IRA (n=20) or IPAA (n=8), and were followed endoscopically over a mean period of 7.47 years. The number and both macroscopic and histological features of polyps before and after surgery, the treatment, and complications were all analyzed. The suitability of the follow-up interval was assessed.Results: none of the 26 patients who complied with follow-up developed rectal cancer. Two patients developed rectal cancer at 21 and 36 months after withdrawing from the protocol. Except in two cas...