Periventricular nodular heterotopia: report of a pediatric series

Periventricular nodular heterotopia is a malformation that occurs in both males and females and is associated with a variety of clinical and neuroradiologic signs. A gene called filamin-1 (FLN-1) has recently been identified. We review the clinical and imaging findings from a series of pediatric patients with periventricular nodular heterotopia. Five patients (three males and two females; age range = 4-18 years) were investigated. In our series, periventricular nodular heterotopia can be the common denominator in different conditions. Periventricular nodular heterotopia can occur alone or be associated with cortical malformations. Epilepsy was present in three of the five patients and was resistant to drugs in one female. Mental retardation was present in three of the five patients. Two male patients had normal intelligence, with no cortical anomalies; patient 3 had unilateral periventricular nodular heterotopia. The associated malformations were more severe in the female patients and slight only in patient 1. The two females showed anomalies rarely reported in association with bilateral periventricular nodular heterotopia. We believe that other genes can be involved in children with atypical neuroradiologic periventricular nodular heterotopia. No mutations were detected in 6 of the 48 exons of the FLN-1 gene, although this does not allow any definitive conclusions to be reached. We conclude that our series of patients with periventricular nodular heterotopia clearly highlights the complexity of the clinical, neurologic, and neuroradiologic characteristics associated with this malformation.