We then looked for changes in WNT signalling components in the PD array databases, reasoning that changes in WNT signalling transcripts might provide a clue to the regulation of the genes showing such a profound depression in PD (ie. SLC18A2, TH, ALDH1A1, SLC6A3 and KCNJ6). The gene discussed is ALDH1A1; the disease is Parkinson disease.