Final answer:
The most common genetic mutation found in LBD is the mutation in the alpha-synuclein gene, leading to the accumulation of alpha-synuclein protein in the brain.
Step-by-step explanation:
The most common genetic mutation found in Lewy Body Disease (LBD) is the mutation in the alpha-synuclein gene. This mutation leads to the abnormal accumulation of alpha-synuclein protein in the brain, forming Lewy bodies. These Lewy bodies are a pathological hallmark of LBD and are associated with the progression of the disease. Other genetic mutations, such as mutations in the Leucine-rich receptor kinase 2 (LRRK2) gene, GBA gene, and SCARB2 gene, have also been implicated in LBD but are relatively less common compared to the alpha-synuclein mutation.