We examined the relationship between RPS18 mRNA levels using ddPCR in PBMCs and PWS symptoms in the total 36 participants: nine were younger than 5 years of age, 12 were between 5 and 12 years of age, 2 adolescents at 13 and 18 years of age and 13 adults between 19 and 45 years of age. This evidence concerns the gene RPS18 and Prader-Willi syndrome.