Congenital hydrocephalus (CH), occurring in approximately 1/1000 live births, represents an important clinical challenge due to the limited knowledge of underlying molecular mechanisms. The discovery of novel CH-genes is thus essential to shed light on the intricate processes responsible for ventricular dilatation in CH Here we identify FLVCR1 (Feline Leukemia Virus Subgroup C Receptor 1) as a novel gene responsible for a severe form of CH in humans and mice. Mechanistically, our data reveal that the heme exporter FLVCR1a interacts with IP3R3-VDAC, a complex located on mitochondrial-associated membranes (MAMs) that controls mitochondrial calcium handling. Loss of Flvcr1 in mouse neural stem cells (NSCs) affects mitochondrial calcium levels and energy metabolism, leading to defective cortical neurogenesis and brain ventricle enlargement. These data point to defective NSC calcium handling and metabolic activity as one of the pathogenetic mechanisms driving CH.