Familial focal epilepsy with variable foci (FFEVF) is an inherited focal epilepsy syndrome in which different members of the same family can have seizures arising from different cortical regions. Even within one person, the seizure focus is usually consistent, but the location varies across relatives.
This unusual family pattern reflects genetic susceptibility to focal epilepsy rather than one shared anatomical lesion.
Where FFEVF fits in ILAE classification
The ILAE recognises FFEVF among focal epilepsy syndromes with onset at a variable age.
It is especially associated with pathogenic variants affecting the GATOR1 complex, including DEPDC5, NPRL2 and NPRL3.
What “variable foci” means
One relative may have frontal lobe seizures, another temporal lobe seizures and another seizures from a different cortical region.
The focus is usually stable within each individual. The variability is primarily between family members.
Seizure semiology
Symptoms depend on the cortical region involved.
Seizures may include focal motor activity, sensory symptoms, autonomic changes, impaired awareness, hypermotor behaviour or progression to bilateral tonic-clonic seizures.
Age at onset
Seizures can begin from childhood through adulthood.
The broad age range and different focal phenotypes can make the underlying family syndrome difficult to recognise.
EEG
The interictal EEG background is usually normal.
Focal epileptiform abnormalities may be present and generally correspond to the individual’s seizure network rather than to one location shared by all relatives.
MRI
MRI can be normal or can show focal cortical dysplasia.
The relationship between GATOR1 genes and cortical malformations is particularly important because some apparently “genetic” focal epilepsies also have a structural substrate.
DEPDC5 and the GATOR1 pathway
DEPDC5, NPRL2 and NPRL3 encode components of the GATOR1 complex, a negative regulator of the mTOR pathway.
Loss-of-function variants can increase mTOR signalling and predispose to focal seizures and focal cortical dysplasia.
Why one inherited variant can produce different focal epilepsies
A germline pathogenic variant creates susceptibility throughout the brain, but additional developmental or somatic events may determine where an epileptogenic cortical abnormality forms.
This “two-hit” concept is one explanation for variable focal locations within the same family.
Incomplete penetrance
Not everyone who inherits a GATOR1 pathogenic variant develops epilepsy.
This incomplete penetrance is important in genetic counselling because a clinically unaffected parent may still transmit the variant.
Sudden unexpected death in epilepsy
Some GATOR1-related families have reported SUDEP, particularly in people with poorly controlled convulsive seizures.
The gene finding itself does not allow individual SUDEP risk to be predicted, but seizure control and standard SUDEP counselling remain important.
Treatment
Treatment follows focal epilepsy principles and depends on the individual’s seizure type and localisation.
Many people respond to medication, while others develop drug-resistant focal epilepsy.
Epilepsy surgery
When MRI or advanced evaluation identifies a focal cortical dysplasia or well-defined epileptogenic zone, surgery can be considered.
Having a germline genetic diagnosis does not automatically make epilepsy “generalised” or rule out a focal surgical target.
mTOR-targeted therapy
Because GATOR1 disorders affect mTOR signalling, mTOR-targeted treatments are an area of research interest.
They are not established routine therapy for FFEVF and should not be presented as a proven replacement for conventional epilepsy treatment or surgery.
Genetic testing
Testing is especially relevant when multiple relatives have focal epilepsies arising from different lobes or when focal cortical dysplasia appears in a familial pattern.
Broader epilepsy panels or exome/genome sequencing can detect GATOR1 and other focal-epilepsy genes.
Worldwide diagnosis
Families may not be recognised as having one syndrome because each relative can appear to have a different focal epilepsy.
Access to genomic testing and high-resolution MRI strongly influences whether the shared mechanism is identified.
The central point
FFEVF is a genetic focal epilepsy in which the seizure focus varies between relatives. The syndrome shows how one inherited molecular pathway can lead to different focal cortical networks in different people.
Related reading
Focal Cortical Dysplasia →
Genetics & Epilepsy →
Epilepsy Surgery and Presurgical Assessment →
Sources
Medical note: a genetic cause does not mean seizures arise everywhere in the brain. Many genetic epilepsies remain anatomically focal.
Evidence checked: September 2026.