KRIT1 and cerebral cavernous malformation: In particular, whereas AKAP9 is known to enhance endothelial barrier function [64], both CYP51A1 and AKAP9, the two KRIT1-flanking genes comprised in the large hemizygous deletion identified in case #7, have been proposed as putative prognostic biomarkers associated with oxidative stress-related diseases [21,65], suggesting a potential role as genetic modifiers of CCM disease expression and severity, which deserves further investigation.