Some experimental evidence of PTM present in the RAI1 protein comes from in vitro studies where the isoform 1 and five RAI1 mutated forms of the protein (RAI1-HA 2687delC, RAI1-HA 3103delC, RAI1 R960X, RAI1-HA Q1562R, and RAI1-HA S1808N, four of them associated with SMS clinical phenotype) were studied. The gene discussed is RAI1; the disease is Smith-Magenis syndrome.