Periventricular Nodular Heterotopias Induced-Seizures in an Adolescent

A female adolescent with no relevant past history was admitted to the Pediatric Emergency Department with two episodes of seizures without trauma, fever, or other symptoms. Head-MRI revealed bilateral subependymal nodular irregularities lining the lateral ventricles, with similar signal evolution to grey matter, confirming the diagnosis of periventricular nodular heterotopias (PVNH). Genetic testing revealed a Filamin A (FLNA) variant; family studies were negative. Further investigation excluded associated comorbidities. PVNH is a rare condition caused by an abnormality in neuronal migration and is part of a phenotypically and genetically heterogeneous group of disorders. FLNA variants are PVNH's most common cause and are responsible for classical neuroradiologic imaging, characterized by bilateral symmetrical nodules with predominantly anterior and mid-body distribution along the linings of lateral ventricles. Classical PVNH typically affects females presenting with seizures in mid-adolescence, with normal/mildly impaired cognition; males are more severely affected. FLNA-induced PVNH may be associated with comorbidities, which may be severe. Other rarer genetic causes combine PVNH with complex brain or systemic abnormalities, resulting in developmental delay and a worse prognosis. Genetic diagnosis is essential for adequate counseling, follow-up, seizure control, vigilance, and treatment of comorbidities, as they may have a great impact on the patient's quality of life.