RPS18 and Prader-Willi syndrome: Increase in RPS18 mRNA levels in peripheral blood mononuclear cells (PBMCs) of another cohort (16 deletion, 20 non-deletion, ages 1–45 years) assessed using droplet digital PCR was found to be associated with intellectual functioning and challenging behaviors, but not autistic traits in children with PWS due to non-deletion (< 13 years old; N = 19).