Epigenomics in Understanding Racial Disparities of Alzheimer's Disease and Related Dementias.

Alzheimer's disease (AD) and related dementias (ADRD) are neurodegenerative conditions that cause gradual deterioration of cognition, memory and language in the elderly. AD has been declared as a health priority by the World Health Organization (WHO) considering its severity and unavailability of a permanent cure. Although the global AD/ADRD population is made up of many ethno-racial groups, the majority of AD studies have focused on the Caucasian population. The few AD studies conducted on minority populations in the US have found that significant AD health disparities exist, demonstrating that African Americans and Hispanics have a significantly higher prevalence of AD and related dementias, with their risk often approaching twice that of White individuals. For the past few years, epigenomic research has played an important role in understanding health disparities among diverse racial and ethnic groups. Unlike genetic studies, which focus on the DNA sequence that one is born with, epigenomics investigates how changes in gene expression due to extrinsic environmental exposures may impact disease pathophysiology. Recent epigenomic studies appear to be promising in not only understanding disease pathology but also in developing diagnostic and therapeutic tools for AD with population specificity. However, there is only a handful of studies and review articles available addressing the epigenomic applications in irradicating racial disparities in AD/ADRD. Therefore, the aim of this review is to discuss the recent findings of epigenomic studies in AD and related dementias, their contribution in irradicating racioethnic disparities and insights into the future direction of their application in precision medicine.