Bilateral periventricular nodular heterotopia in a couple mother-infant. Bilateral periventricular nodular heterotopia (BPNH) is a malformation of neuronal migration, recently recognized X-linked. We report a case of BPNH associated with mega-cisterna magna diagnosed by ultrasound imaging at 27 weeks' gestation and confirmed by MR at 11 days of life. Similar findings in the mother's MR underlines the recurrency of this malformation in the same family.