Mechanism-based treatment in tuberous sclerosis complex.
BACKGROUND
Tuberous sclerosis complex (TSC) is a genetic multisystem disorder that affects the brain in almost every patient. It is caused by a mutation in the TSC1 or TSC2 genes, which regulate mammalian target of rapamycin (mTOR), a key player in control of cellular growth and protein synthesis. The most frequent neurological symptoms are seizures, which occur in up to 90% of patients and often are intractable, followed by autism spectrum disorders, intellectual disability, attention deficit-hyperactivity disorder, and sleep problems. Conventional treatment has frequently proven insufficient for neurological and behavioral symptoms, particularly seizure control. This review focuses on the role of TSC/mTOR in neuronal development and network formation and recent mechanism-based treatment approaches.


METHODS
We performed a literature review to identify ongoing therapeutic challenges and novel strategies.


RESULTS
To achieve a better quality of life for many patients, current therapy approaches are directed at restoring dysregulated mTOR signaling. Studies in animals have provided insight into aberrant neuronal network formation caused by constitutive activation of the mTOR pathway, and initial studies in TSC patients using magnetic resonance diffusion tensor imaging and electroencephalogram support a model of impaired neuronal connectivity in TSC. Rapamycin, an mTOR inhibitor, has been used successfully in Tsc-deficient mice to prevent and treat seizures and behavioral abnormalities. There is recent evidence in humans of improved seizure control with mTOR inhibitors.


CONCLUSIONS
Current research provides insight into aberrant neuronal connectivity in TSC and the role of mTOR inhibitors as a promising therapeutic approach.
Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
Kristina
K
Jülich
Department of Neurology, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: mustafa.sahin@childrens.harvard.edu.
Mustafa
M
Sahin
D000818:Animals; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D002659:Child Development Disorders, Pervasive / Q000503:physiopathology; D006801:Humans; D009435:Synaptic Transmission / Q000502:physiology; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D014402:Tuberous Sclerosis / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology*
C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases
mTOR; neuronal connectivity; rapamycin; tuberous sclerosis complex