FMR1 and major depressive disorder: Children with the premutation present with more frequent diagnoses of Attention Deficient Hyperactivity Disorder (ADHD), autism spectrum disorder (ASD), anxiety, and social difficulties, whereas adult PMCs primarily present with increased rates of anxiety and depression, particularly in females, who are twice as likely to have a premutation status than males due to the location of the FMR1 gene on the X chromosome (Hunter et al., 2014; Cordeiro et al., 2015; Hagerman et al., 2018).