A Decade of the Common FTO rs9939609 Polymorphism: A Systematic Review
Several association studies focusing on FTO gene polymorphisms have been published in the past years; however, the association between FTO -related conditions and FTO gene variants remains unexplained. Population genetics and association studies of different populations provide a valuable tool for further research. Thus, the aim of this systematic review is to summarize current knowledge on the FTO SNP rs9939609, and its association with presumably related conditions. The study included original research articles collected from PubMed and ResearchGate databases that were published in the period between 2007 and November 2017, and that provide information on rs9939609 mutant allele frequency and its probable association with any condition suspected of being related to the mutant allele. Genotype data was extracted and analyzed, and missing data was obtained from secondary sources. Short summaries of relevant studies from primary sources are organized in an overview table. The results of the systematic review suggest that mutant allele A is the most prevalent in European populations and least frequent on the Far East. In addition, it has been concluded that allele A is a good tool for the prediction of an increased risk of higher-than-normal BMI in a person carrying it, as well as that allele A should be further analyzed as a possible risk marker for type 2 diabetes mellitus and polycystic ovary syndrome development.