Clinical and genetic features in patients with MutYH-associated polyposis

Aim. MutYH-associated polyposis is a rare polyposis syndrome with an autosomal recessive type of inheritance, phenotypically often similar to an attenuated form of Familial adenomatous polyposis (FAP). In different populations, patients with MAP have clinical and genetic features. The article presents the features of the clinical picture and the spectrum of mutations in the MutYH gene in patients with MutYH-associated polyposis in the Russian population. Materials and methods. The material for the study was clinical data of 20 patients with a genetically confirmed diagnosis of MutYH-associated polyposis underwent treatment at National Medical Research Centre for Coloproctology named after A.N. Ryzhikh». Results. The male to female ratio among patients with MAP was 7:13. The average age of diagnosis was 49.7 (19-70) years. The average number of polyps in the colon was 91 (24-420), while in most patients (70%; 14/20) they were distributed evenly in all parts of the colon, in 6 patients, most were located in the right sections. The most common pathogenic mutations in the MutYH gene were missense mutations p.G382D (33%; 13/40), p.Y165C (15%; 6/40), p.G169D (15%; 6/40) and p .R231H (15%; 6/40), also found in two patients c.462 + 19_462 + 31del. The frequency of other mutations that occurred only once was 17% (7/40). It was revealed that 12 out of 20 patients (60%) had colorectal cancer (CRC) at the time of MAP diagnosis, while the average age for diagnosing MAP without CRC was 37.5 (19-50) years, and the average age of CRC diagnosing for patients with MAP background - 57.9 (42-70) years. Conclusions. Clinical and genetic characteristics of patients with MutYH-associated polyposis were identified in the Russian population.