While studying mice, he learned that the disease allows a neuron's mGluR5 receptor to send out a flurry of signals telling the cell to produce protein. The protein overload causes a neuron to form many more connections to other neurons than normal, creating chaos by spreading nerve instructions to too many cells. Bear's drug, called STX107, inhibits the receptors to pare back the overproduction of proteins associated with Fragile X to a normal range. His company, Seaside Therapeutics, plans to test STX107 in patients this fall. If it works as well as it did in mice, Bear says, it could be a first step to treating other causes of autism.