In recessive transmission, misfolded proteins remain trapped by lumenal chaperones in the ER, precluding oligomerization with wild type alleles; e.g., many hyperekplexia variants in GLYT2 (Eulenburg et al., 2006; Rees et al., 2006) or parkinsonism variants in DAT (Kurian et al., 2009, 2011; Ng et al., 2014). Here, SLC6A3 is linked to Parkinson disease.