TH and Parkinson disease: The neuronal cells derived from αSyn A53T PD patient iPS cells exhibited an accumulation of αSyn serine 129 phosphorylation (αSyn-pS129), a specific pathological αSyn form [2], and shorter neurites of dopaminergic neurons immunopositive for anti-tyrosine hydroxylase (TH), relative to neurons derived from isogenic corrected control iPS cells (Suppl Fig. 2).