Investigators at Children's Memorial Health Institute, Warsaw, Poland, report monozygotic twin sisters with tuberous sclerosis complex (TSC), one treated with the mTOR inhibitor everolimus since age 4 years. After 24-month follow-up, everolimus treatment was associated with a significant decrease in brain tumor volume, and the treated twin presents no facial angiofibroma, and no renal angiomyolipomas (AMLs). The brain tumor in the nontreated sister is stable in size, but she has developed facial angiofibroma and renal AMLs. Early mTOR inhibition in TSC patients may prevent the development of TSC lesions and alter the natural history of the disease. 
COMMENT. The approach to the management of tuberous sclerosis complex (TSC) has become more demanding because novel TSC-specific treatments are now available, and indications for intervention vary with age and organ system. Periodic MR imaging is advised every 1-3 years to exclude development of subependymal giant cell astrocytoma and need for treatment with everolimus, negating the need for invasive surgery. Routine EEG in asymptomatic TSC infants for the first year or two of life is increasingly accepted, with treatment initiation of vigabatrin if indicated at the earliest sign of developing hypsarrhythmia.