Activating p110α mutations are linked to both cancer (Samuels et al., 2004; Vasan et al., 2019) and overgrowth disorders (Lindhurst et al., 2012), while activating p110δ mutations are linked to primary immuno-deficiencies (Dornan et al., 2017; Lucas et al., 2016; Angulo et al., 2013). This evidence concerns the gene PIK3CD and immunodeficiency disease.