GRP and Parkinson disease: When compared with their ancestral GRP cells, GDAsBMP showed a > 600-fold increase in levels of THBS2 mRNA, and a > 2000-fold increase in mRNA levels for THBS1, two of the most potent molecules for promoting synaptic efficacy (Liauw et al, 2008) and dendritic spine formation (Garcia et al, 2010), processes known to be compromised in PD (Bezard, 2010; Ingham et al, 1989; McNeill et al, 1988; Nitsch & Riesenberg, 1995; Soderstrom et al, 2010).