A study on α-synuclein inducible transgenic mice, which selectively expressed human PD-related A53T α-synuclein in astrocytes, showed that excess A53T α-synuclein in astrocytes caused severe astrogliosis, leading to dysfunction of astrocytes to maintain the integrity of BBB and homeostasis of extracellular glutamate. This evidence concerns the gene SNCA and Parkinson disease.