625 EMRs were reviewed. 102 were classified as EOD, yielding a prevalence of 16.3%. 54 (52.9%) were females. Mean age at onset was 56.8 years. Mean years of education was 8.48. Etiologies found were Alzheimer’s (40; 39.2%), Vascular dementia (7; 6.8%), Alzheimer’s and vascular (5; 4.9%), Frontotemporal dementia (12; 11.7%), dementia with parkinsonian features - LBD, PSP, MSA (5; 4.9%), multifactorial (9; 8.8%), others (11; 10.7%), and unknown/under investigation (13; 12.7%). No differences were found when comparing age at onset, age at admission, initial MMSE and schooling years among different causes. Positive first-degree family history of dementia was frequent (36.2%). Genetic causes included mutations in PSEN1, APP and TYROBP.