Fat Mass and Obesity-Associated Gene (FTO) is abundantly expressed in most organs. The gene product is an AlkB-like DNA/RNA demethylase with a strong preference for single stranded DNA and RNA. Single nucleotide polymorphisms (SNPs) in the first intron of the FTO gene contribute to childhood obesity and severe adult obesity. Knockout or loss-of-function of FTO produces an autosomal-recessive lethal syndrome with multiple malformations and severe growth retardation. FTO is the first locus unequivocally associated with adiposity, with activity within the central nervous system apparently regulating feeding behavior and energy expenditure. Cayman's FTO (intracellular; human) EIA Kit is an immunometric assay which can be used to measure FTO in human cell lysates. The assay exhibits a detection limit of 50 pg/ml and an assay range of 0-10 ng/ml.