Case of Early-onset Dementia with Lewy Bodies Associated with PRKN Gene Mutation

Dementia with Lewy bodies is the second most common neurodegenerative form of dementia following Alzheimer’s disease, affecting 0.4% of people over the age of 65 every year. It is more commonly diagnosed in men than in women, and typically over the age of 50. It is a synucleinopathy, in which alpha-synuclein inclusions accumulate in neurons, similar to idiopathic Parkinson’s disease and multiple system atrophy. Clinical features include cognitive decline, bradykinetic movements, and visual hallucinations. Neuroimaging in dementia with Lewy bodies typically reveals occipital and parietal lobe atrophy and hypometabolism. Some cases of dementia with Lewy bodies and idiopathic Parkinson’s disease have been shown to be associated with genetic mutations, such as in the GBA gene. In this case report, we present a unique case of a young woman who started showing clinical features of dementia with Lewy bodies at the age of 44, with further confirmation of the diagnosis from neuroimaging studies. However, her genetic test results revealed the presence of a PRKN gene mutation, which has been described with Parkinson’s disease, even though she did not show typical clinical features of this disease. This report reveals a potential unique association of the PRKN mutation with early-onset dementia with Lewy bodies, indicating that we may have an incomplete understanding of the function of such genes in cognitive development, as well as the phenotypic presentations of dementia with Lewy bodies and Parkinson’s disease.