FOXP1 and Down syndrome: The R465 and R514 residues are recurrently mutated, with R465G and R514C mutations detected in patients with FOXP1 syndrome, with a characterized clinical symptom of developmental retardation (Hua et al, 2021; Siper et al, 2017; Sollis et al, 2016); and R465T, R514C, and R514H mutations in a broad spectrum of tumor tissues as indicated in TCGA database.