This case report illustrates the phenotypic variability associated with 15q11.2 microdeletion syndrome (BP1-BP2) in a six-year-old male. Specifically, we highlight the rare combination of early-onset refractory epilepsy, schizencephaly, a rare congenital brain malformation in which a cerebrospinal fluid-filled cleft, lined with gray matter, extends from the brain surface to the ventricle, and cystic fibrosis transmembrane conductance regulator (CFTR) variant carrier status, which adds to the uniqueness of the case [4]. This evidence concerns the gene CFTR and Down syndrome.