Interestingly, subsequent genetic screening using a Drosophila model of FXTAS revealed that knockdown of CG4306, the fly ortholog of Gamma-glutamylcyclotransferase (Ggct), which encodes the enzyme responsible for catalyzing the formation of 5-oxoproline (Oakley et al., 2008), resulted in suppression of (CGG)90 toxicity in Drosophila. This finding suggests Ggct as a genetic modifier of CGG-associated neurotoxicity (Kong et al., 2019), providing a novel therapeutic target for FXTAS. This evidence concerns the gene GGCT and fragile X-associated tremor/ataxia syndrome.