Dr. Maria Lehtinen Elucidates the Genetics Behind Brain and Speech Development

In a new study published in Neuron, a team from Boston Children’s Hospital led by NYSCF – Robertson Neuroscience Investigator Maria Lehtinen, PhD, discovered that a gene called SCN3A (which regulates a sodium channel) plays a significant role in brain and oral motor development.

The team studied patients with polymicrogyria, a disease resulting from mutations in SCN3A. MRI scans revealed that these patients had smaller, malformed brain folds in areas that control speech and language, often leading to difficulty articulating words and a delay in language skills. The team then mutated SCN3A in the brains of newborn ferrets and observed that the ferrets also showed abnormal brain folding and cortical development.

Sodium channels are important because they help neurons send signals to each other. Many mutations in sodium channels lead to epilepsy, but patients with polymicrogyria are rarely epileptic. The team believes that polymicrogyria differs from other sodium channel-related diseases (like epilepsy) because SCN3A acts earlier in development.

Notably, because mutations in SCN3A do not always cause severe complications like epilepsy, milder mutations in SCN3A leading to oral motor difficulties are probably more common in the general public than expected. These patients are unlikely to seek out an MRI, so the cause of their symptoms may go undetected.

Very few studies have examined the connection between cortical malformations and problems with oral motor function and language development. Dr. Lehtinen’s team hopes that their research will open the door to a better understanding of complex developmental processes involving speech, language, and the brain.