Brain somatic mutations in Alzheimer's disease: linking genetic mosaicism to neurodegeneration.

Somatic mutations are DNA sequence changes that occur in non-reproductive cells during an organism's life and are not inherited by offspring. Growing evidence implicates somatic mutations in Alzheimer's disease (AD), linking them to both disease onset and progression. Recent advancements in single-cell sequencing and genome-wide analyses have revealed higher mutation burdens in neurons, particularly in AD-related genes such as Presenilin 1 (PSEN1), Presenilin 2 (PSEN2) and amyloid precursor protein (APP). These mutations, which include single nucleotide variants (SNVs), small insertions and deletions (Indels), structural variations (SVs) and mitochondrial DNA (mtDNA) mutations may disrupt neuronal function and synaptic connectivity. However, some somatic mutations may also serve a neuroprotective role. The underlying mechanisms remain incompletely understood. This review explores the emerging role of somatic mutations in AD, highlighting their links to disease progression. It also underscores the potential for future research to uncover new therapeutic targets by integrating advanced sequencing technologies and gene-editing approaches, which may enable more precise interventions to correct somatic mutations and slow disease progression.