PIK3CA and cerebral cavernous malformation: While whole genome sequencing cannot be used to determine whether or not allelic imbalance encompassing CCM genes occurs in the same population as activating PIK3CA variants, orthogonal validation of allelic imbalance in CCM 5078 suggests MoChA is capable of identifying allelic imbalance in CCMs when the region of loss encompasses large enough regions, such as an entire chromosome in this instance, or is in a large enough number of cells.