RYK and Parkinson disease: Consistent with the idea of a loss of β-catenin-dependent WNT signalling is a PD associated increase in multiple membrane bound WNT signalling components (RYK, ROR2, LGR5, LGR5, FZD7, FZD9), along with increased WNT1, 2B and 11, as well as WIFI and DKK2.