ABSTRACT
Objective:To summarize the clinical and gene mutation characteristics of a child with Cowden syndrome and review the literature.Methods:The clinical data of a child with Cowden syndrome treated in the First Affiliated Hospital of Xinxiang Medical University in June 2020 were analyzed retrospectively.Taking " Cowden syndrome" , " PTEN gene" , " hamartoma polyps" , "child" , " Cowden syndrome and child" and " PTEN and child" as key words, literature was retrieved from Chinese databases (China National Knowledge Internet database and Wanfang database) and the PubMed database from the establishment of the database to March 2021. Results:A 13-year-old male had intermittent abdominal pain and abdominal distension for 5 months.Electron microscopic gastroenteroscopy showed multiple polyps, and focal lymphocyte aggregation and infiltration were found in tissue biopsy.Whole exon sequencing revealed a hemizygous mutation of c. 475 (exon5) A>T in PTEN gene, which led to the transformation of the 159 th amino acid from arginine to tryptophan.The prediction results of the tertiary structure of the protein indicated that the variation might affect the spatial structure of the protein and damage the protein function.According to the clinical characteristics, Cowden syndrome was diagnosed.The pedigree confirmed that the variation was inherited from the mother, who had a similar phenotype.No qualified Chinese report was retrieved.Among 41 English studies on PTEN gene mutation in children, there were only two reports related to pediatric Cowden syndrome.The hemizygous mutation of PTEN gene was not reported. Conclusions:The missense mutation of c. 475 (exon5) A>T in PTEN gene in this study is a novel cause of Cowden syndrome, and the case is the first case report in China.