mTOR-pathway epilepsies (mTORopathies)

What mTOR-pathway epilepsies are

The mTOR pathway is a master regulator of cell growth. When it is overactive — because of an inherited or, often, a brain-only (somatic mosaic) genetic change — neurons can grow and wire abnormally, producing malformations of cortical development and epilepsy that frequently resists standard medicines.

Some of these conditions affect the whole brain or body (such as tuberous sclerosis complex), while others are confined to one region (focal cortical dysplasia) — and in focal cases the causative variant may be present only in the affected brain tissue, detectable in tissue removed at surgery.

Diagnosis

Assessment combines high-quality MRI (to identify a cortical malformation), EEG and, increasingly, genetic testing of blood and — where surgery is performed — of brain tissue, which can reveal somatic variants not seen in blood. Identifying an mTOR-pathway cause helps explain the epilepsy and points toward targeted treatment.

Treatment and the precision approach

For focal malformations such as focal cortical dysplasia, epilepsy surgery (removing the abnormal area) offers the best chance of seizure freedom and remains a cornerstone of care. Alongside this, mTOR inhibitors — everolimus and sirolimus — directly target the overactive pathway: everolimus is established for tuberous sclerosis–associated seizures, and this 'precision' strategy is being studied across other mTORopathies.

How an educational review can help

An educational review can explain MRI and genetic findings, clarify whether an mTOR-pathway cause is likely, and put options such as epilepsy surgery and mTOR-inhibitor treatment in context, helping you prepare questions for your treating team. It is educational and does not replace your clinician's care.