For instance, patients with schizophrenia have been found to have reduced levels of transthyretin and altered nicotinic receptor signaling has been associated with schizophrenia in humans and animal models (Diwan et al., 1998; Wan et al., 2006; Koukouli et al., 2017), suggesting a potential relevance of choroid plexus function in the disease state. This evidence concerns the gene TTR and schizophrenia.