YOUNG-ONSET DEMENTIA IN A SOUTHEAST ASIAN POPULATION FROM SINGAPORE: CLINICAL AND BIOMARKER CHARACTERIZATION

Abstract

Patients with Young onset dementia (YOD) are less likely to have mixed pathology, have a higher genetic predisposition and thus detailed characterization of this cohort may offer an opportunity for biomarker development and discovery of novel drug interventions. Existing Asian YOD cohorts are largely from Japan and thus little is known about the clinical and biomarker profile of YOD in Southeast Asia. We present the clinical and biomarker characteristics of Southeast Asian YOD patients from multiethnic Singapore. Patients were recruited from the National Neuroscience Institute beginning January 2012. Beginning July 2015, additional biomarker data including volumetric MRI, genetics and cerebrospinal fluid (CSF) were collected. Volumetric MRI was performed on a 3T Siemens machine. CSF Amyloidβ, total tau and phosphor-tau were performed using ELISA techniques. Diagnosis of dementia was made at consensus meetings comprising of cognitive neurologists, neuroradiologists, psychologists and dementia nurses. Alzheimer's disease (AD) was diagnosed based on the NIA-AA criteria, Vascular Dementia (VaD) based on the NINDS-ADRDA criteria and Frontotemporal Dementia (FTD) based on the Rascovsky criteria. MCI was diagnosed based on the Petersen's criteria. A total 309 patients were recruited between 2012 and Dec 2016. There were 250 patients with dementia (N, AD=145, VaD=30, FTD=48) and 59 patients with MCI. Mean (SD) age of onset for AD, VaD and FTD was 56.77 (5.06), 56.84 (5.61) and 56.60 (5.32) respectively. Family history of YOD among first degree relatives were present in 28.7% of AD, 10.0% of VAD and 22.9% of FTD. Of the 143 patients with Young Onset AD, 90.9% had amnestic AD, 2.1 % had behavioral variant AD and 1.4% had logopenic variant and 5.6% had Posterior Cortical Atrophy type of AD. 39.0% consented for CSF analyses. Further analyses with clinical, neuropsychological, volumetric MRI and CSF findings are on-going. This is the first report of YOD in Southeast Asians. AD continues to be the major subtype of YOD. Non-amnestic AD is present in about 10% and 29% of Young AD have a positive family history. Greater awareness on the clinical presentation of YOD among Southeast Asians is needed for earlier diagnosis and timely intervention.