Synaptic vesicle neurotransmitter transporter and smart storage PG, SV2A, SV2B, SV2C paralogs share 60% sequence and 80% structural homology. SV2A controls neurotransmitter release (Nowack et al. 2010; Wan et al. 2010), SV2B is expressed in the retina (Morgans et al. 2009), SV2C modulates dopamine release and is disrupted in Parkinson disease (Dunn et al. 2017). The gene discussed is SV2B; the disease is Parkinson disease.