RBC acetyl cholinesterase: A poor man's early diagnostic biomarker for familial alzheimer's and Parkinson's disease dementia

OBJECTIVE: Analysis of red blood cell acetyl cholinesterase (AChE) in a familial Alzheimer's diseases (AD) Parkinson's disease dementia (PDD) and their first generation. SETTING: General hospital, Mahad district, Raigad. PATIENTS AND METHODS: Clinically diagnosed patients of AD and PDD and their asymptomatic relatives. Their blood was collected in EDTA tube and transferred to laboratory at Mumbai. RESULT: Median red blood cell (RBC) cholinesterase levels amongst PDD, their first generation asymptomatic relatives, familial AD, asymptomatic relatives of AD, healthy controls, farmers exposed to pesticides (positive control) and other neurological condition without dementia (hypertension with TIA 1, sub-dural hematoma 2, hypothyroid 1, non-familial unilateral parkinsonism without dementia 3, writers cramps 2, hyponitremia 1 and cerebral palsy with non-fluent aphasia 1). Median values of RBC AChE were 19086.78 U/L, 15666.05 U/L, 9013.11 U/L, 7806.19 U/L, 14334.57 U/L, 9785.05 U/L and 13162.60 U/L, respectively. As compared to controls, RBC AChE levels were statistically significant among PDD (P = 0.004) and significantly lowered among familial AD patients (P = 0.010), relatives of patients (P = 0.010). INTERPRETATIONS: Below the normal RBC AChE level is a potential biomarker in asymptomatic relatives of familial AD patients. RBC AChE is raised than normal level in patients suffering from PDD, where AChE inhibitors are helpful. However, RBC AChE level below the normal where AChE inhibitor may not be effective.