Progressing towards blood based diagnostic RNA biomarkers for dementia with lewy bodies

Abstract

Prevalence of Dementia with Lewy bodies (DLB) is second only to Alzheimer's disease (AD) among people with neurodegenerative dementia. Accurate distinction between these two most common subtypes of dementia is essential because they differ in their prognosis, neuropsychiatric symptoms, pharmacological management, 1 and sensitivity to medication adverse effects. Misdiagnosing DLB as AD, and prescribing an antipsychotic medication for treating persistent visual hallucinations and associated challenging behaviours may lead to life-threatening adverse events. Moreover, DLB leads to earlier institutionalisation and mortality, more severe neuropsychiatric symptoms, higher costs and more carers’ burden than AD. Currently, there are only three indicative biomarkers helping to diagnose DLB, 1) reduced dopamine transporter uptake in basal ganglia, visualised by Single-Photon Emission Computed Tomography or Positron Emission Tomography, 2) low uptake 123iodine-Meta-iodobenzylguanidine myocardial scintigraphy, and 3) polysomnography confirming rapid eye movement sleep without atonia. 2 These indicative biomarkers are not routinely used in most clinical settings because of costs, equipment availability or concerns over feasibility. There is an urgent clinical need for discovering reliable blood-based biomarkers that can aid differentiating DLB from AD. Such blood-based diagnostic biomarkers hold promise for rapid clinical adoption and for facilitating early diagnosis and accurate subtyping of dementia.