PIK3CA and polymicrogyria: However, patients 1 and 9 in our study, who had somatic PIK3CA mutations, did not present with somatic features observed in MCAP other than syndactyly [47], whereas patients 3, 4 and 5 who did not have PIK3R2 mutations, presented with megalencephaly, polymicrogyria or ventriculomegaly, consistent with MPPH.