[11C]UCB-J is a PET tracer for imaging the synaptic vesicle protein 2 A (SV2A) that is ubiquitously expressed in the synapses in human brains and has garnered interest as an important biomarker of synaptic loss in various disorders including schizophrenia, Alzheimer’s disease, and substance use disorders [1]. Here, SV2A is linked to early-onset autosomal dominant Alzheimer disease.