UCLA researchers have discovered that an FDA-approved drug reverses the brain dysfunction caused by tuberous sclerosis complex (TSC); because half of TSC patients also suffer from autism, the researchers are hopeful the treatment can address associated learning disorders. The journal Nature Medicine published the findings in its June 22 online edition.

The scientists used the drug rapamycin on mice models of TSC; rapamycin is well-known for targeting an enzyme involved in creating proteins needed for memory. The same enzyme is also regulated by TSC proteins.

"This is the first study to demonstrate that the drug rapamycin can repair learning deficits related to a genetic mutation that causes autism in humans. The same mutation in animals produces learning disorders, which we were able to eliminate in adult mice," said lead investigator Alcino Silva, professor of neurobiology and psychiatry at the David Geffen School of Medicine at UCLA. "Our work and other recent studies suggest that some forms of mental retardation can be reversed, even in the adult brain."

The researchers studied mice bred with tuberous sclerosis complex and confirmed that the animals suffered from the same severe learning disabilities as human patients. The learning problems were tied to biochemical changes and abnormal functioning of the hippocampus, a brain structure that plays a vital role in memory.

"After only three days of treatment, the TSC mice learned as quickly as the healthy mice," said first author Dan Ehninger, postgraduate researcher in neurobiology. "The rapamycin corrected the biochemistry, reversed the learning deficits and restored normal hippocampal function, allowing the mice's brains to store memories properly."