Non-coding RNA biomarkers in Alzheimer's disease.

Alzheimer's disease (AD) is the most prevalent cause of dementia among elderly individuals and is characterized by progressive cognitive decline, memory impairment, and the accumulation of amyloid-beta (Aβ) plaques and neurofibrillary tangles in the brain. Despite extensive research, current therapeutic approaches remain limited to symptomatic relief and are unable to halt disease progression. This challenge highlights the urgent need for reliable biomarkers that enable early diagnosis and facilitate the development of targeted interventions. Noncoding RNAs (ncRNAs) have recently emerged as promising biomarkers because of their regulatory roles in gene expression and cellular function. Among them, microRNAs (miRNAs) have revolutionized our understanding of neurodegenerative processes, with evidence linking their dysregulation to AD pathology. Additionally, circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), and PIWI-interacting RNAs (piRNAs) have been implicated in neuronal survival, synaptic maintenance, and amyloid precursor protein processing, further expanding the biomarker landscape. This review examines the expression patterns, functional significance, and diagnostic potential of ncRNAs in AD, alongside methodological approaches for their detection. By bridging molecular insights with translational applications, we explore how ncRNAs may redefine AD diagnostics and therapeutic strategies in the future.