PIK3CA and neurodevelopmental disorder: Among the common pathogenic variants associated with these neurodevelopmental disorders, sometimes referred to as ’mTORopathies” (reviewed in (35), are mutations of PIK3CA or MTOR. The PIK3CA p.H1047R variant is the most common hyperactivating mutation in the catalytic p110 subunit of the PI3K holoenzyme that renders it resistant to inhibition by the p85 regulatory subunit, increasing the basal PI3K activity (36, 37).