Tuberous sclerosis complex

What it is

Tuberous sclerosis complex (TSC) is a genetic condition that causes benign tumors to grow in various organs, including the brain. In the glioma context, it is associated with subependymal giant cell astrocytoma (SEGA), a benign-behaving brain tumor that is often treatable with a targeted drug.

Understanding Tuberous sclerosis complex

TSC results from changes in the TSC1 or TSC2 genes, which lead to overactivity of a growth-signaling pathway (the mTOR pathway). This causes various benign tumors and other features. The most relevant brain tumor is SEGA, which arises near the ventricles and can block the flow of cerebrospinal fluid, causing hydrocephalus. People with TSC are monitored with periodic brain imaging to detect SEGAs. A notable advantage is that SEGAs respond to mTOR inhibitor drugs (such as everolimus), which can shrink them — providing a non-surgical option, especially valuable given the underlying pathway. Surgery is also used when needed. TSC illustrates how the underlying genetic pathway can be directly targeted. Understanding tuberous sclerosis and gliomas clarifies a genetic condition associated with the often-targetable SEGA.

Why it matters

Understanding tuberous sclerosis and gliomas helps families see why people with TSC are monitored for SEGAs — and that these tumors can often be treated with a targeted drug that addresses the underlying pathway.