PTEN and activated PI3K-delta syndrome: In this review, we discuss the clinical and immunological features of Activated PI3-Kinase Delta Syndromes - Activated PI3-Kinase Delta Syndrome 1 (APDS1) and Activated PI3-Kinase Delta Syndromes 2 (APDS2) and the APDS-Like (APDS-L) condition PTEN deficiency.