~20 other PIK3CA mutant alleles have been seen in MCAP, characterized by MEG or MEG-PMG, hydrocephalus and less severe epilepsy (Gymnopoulos et al., 2007; Mirzaa et al., 2012; Rivière et al., 2012; Tatton-Brown and Weksberg, 2013). This evidence concerns the gene PIK3CA and Hydrocephalus.