Periventricular nodular heterotopia (PVNH) is a malformation of cortical development in which clusters of neurons remain beside the brain’s ventricles instead of completing normal migration to the cortex. Epilepsy is a frequent presentation.
What does PVNH look like?
On MRI, nodules of grey matter are seen along the ventricular walls. They may be unilateral or bilateral, single or multiple, and may occur with additional cortical or structural abnormalities.
Genetic causes
Some forms are associated with variants in FLNA, especially bilateral PVNH, but PVNH is genetically heterogeneous. Genetic counselling and testing may be appropriate depending on the pattern and associated features.
Epilepsy
Focal seizures are common and can begin in childhood, adolescence or adulthood. Some people respond well to medication; others develop drug-resistant epilepsy.
The nodule is not always the whole seizure network
Electrophysiological studies show that seizures may involve the heterotopic nodule, overlying cortex, mesial temporal structures or distributed networks. This is why simply seeing a nodule on MRI does not automatically identify the tissue that must be treated.
Presurgical investigation
Drug-resistant cases may require video-EEG, PET, SPECT, MEG and invasive stereo-EEG to define the epileptogenic network. Deep location and bilateral disease can make evaluation complex.
Treatment options
Depending on the network, treatment can include resection, laser ablation, radiofrequency thermocoagulation or other focal approaches. Suitability is highly individual.
Current evidence
A 2026 systematic review of childhood-onset PVNH-associated epilepsy emphasised that invasive evaluation is often required because seizure networks can extend beyond the nodules themselves.
Related reading
What PVNH represents
Periventricular nodular heterotopia results when groups of neurons fail to migrate normally to the cortex during development and remain as nodules along the ventricular walls.
Genetics
FLNA-related disease is a major recognised cause, particularly in females with bilateral nodules, but PVNH is genetically heterogeneous and can also occur sporadically. Some genetic forms include cardiovascular or connective-tissue manifestations that require attention beyond epilepsy.
Seizure networks are often distributed
The heterotopic nodule may participate in seizures, but the epileptogenic network can also involve overlying cortex, hippocampus or several connected regions. This is why simply removing a visible nodule is not always sufficient.
SEEG and targeted treatment
Stereo-EEG can help identify whether seizures begin in one nodule, cortex, hippocampus or a broader network. Selected patients may then be considered for resection, ablation or SEEG-guided radiofrequency thermocoagulation.
Cognition
Intelligence can be normal, but reading, executive, language or other neurodevelopmental difficulties occur in some people and may be more prominent in extensive malformation.
Sources and further reading
- Treatment of Epilepsy Associated with Periventricular Nodular Heterotopia. 2020. PMID: 33123826.
- Neurosurgical management of childhood-onset epilepsy in periventricular nodular heterotopia: A systematic review. 2026. PMID: 42669252.
Evidence checked: September 2026.