DNA methylation effects of halogenated and organophosphate-based flame retardants: a mini-review

Abstract Flame retardants are compounds that are extensively used in household products, building materials, automobiles, and electrical goods to suppress the intensity of flames that will increase escape time during a fire. The fundamental issue with these chemicals is that a lot of them are additives, migrate from end-use items into the environment, and exert harmful effects on living organisms. A critical mechanism through which xenobiotics cause adverse effects is epigenetic modifications, which can have profound effect on development and physiology. As we know, the epigenome regulates gene expression through various modifications like DNA methylation, histone modification, and non-coding RNAs. Therefore, disruption of epigenetic control by environmental contaminants is an emerging area of concern to understand their impact on disease vulnerability and health status. DNA methylation is the most studied and key epigenetic regulator during embryogenesis and tissue homeostasis. It predominantly occurs at CpG sites and can cause gene silencing and affect downstream signaling by preventing transcription. Aberrant methylation patterns are related to impaired early embryonic development, neurological disorders, metabolic dysregulation, oxidative stress, and cancer. This review focuses on the ability of flame retardants to affect DNA methylation patterns in the genome and related disorders in exposed organisms.