Clinical phenotype of the PIK3R1-related vascular overgrowth syndrome

Here we report 19 additional patients with PIK3R1 mosaic variants with clinical phenotyping, showing that the PIK3R1 phenotype is indistinguishable from the PIK3CA-related phenotypes, although the megalencephaly-capillary malformation phenotype is consistently absent in patients with PIK3R1 variants. 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’.