FMR1 and fragile X syndrome: Several reports during the last 3 decades demonstrated de novo deletions (Tarleton et al., 1993; Gu et al., 1994; Petek et al., 1999; Luo et al., 2014; Zink et al., 2014; Jorge et al., 2018; Myers et al., 2019) spanning the FMR1 or both the FMR1 and FMR2 gene (Clarke et al., 1992; Wolff et al., 1997; Fengler et al., 2002; Probst et al., 2007), resulting in the loss of FMRP and a range of phenotypes including physical, cognitive and behavioral features, intellectual disabilities (ID), seizures, and obesity, similarly observed in individuals with FXS (Coffee et al., 2008).