APOE and Schnyder corneal dystrophy: In contrast, the association between CSF ApoE levels and dementia progression risk shows inconsistent results: some studies indicate that higher CSF ApoE levels were associated with increased dementia progression risk in individuals with APOEε4 allele in SCD or MCI [50], while others have found that lower CSF ApoE levels were associated with higher dementia progression risk in MCI [49].