SSTR4 and Alzheimer disease: This study involved the relationship between the SSTR4 genotype and AD, but did not examine the methylation of SSTR4. Another study interviewing the same participants revealed that the SSTR4 promoter region was methylated in 21.6% of patients with AD and only 2.3% of controls (Berent et al., 2017b), suggesting a difference in methylation levels of SSTR4 between AD cases and controls.