Here we report 19 additional mosaic PIK3R1 patients with clinical phenotyping, showing that the PIK3R1 phenotype is indistinguishable from the PIK3CA-related phenotypes, although the MCAP phenotype is consistently absent in PIK3R1 patients. We also report novel PIK3R1 variants. We consider that the meaning of PROS should shift from “PIK3CA-related overgrowth spectrum” to “PI3-kinase-related overgrowth spectrum”.