Additional Study Information: We are recruiting families with members under the age of 65 who have dementia or are experiencing memory problems. Our initial screening can be completed in person or over the phone. The evaluation will take about 1 to 1.5 hours per person and includes a: 1. Blood sample (5 tablespoons) or saliva (1 teaspoon) collection: These blood samples will allow us to examine genes to identify causative mutations. 2. Brief Neuropsychological Assessment. 3. Medical History: A research physician will collect basic medical information on you and your family. This assessment will provide information on other risk factors that could be potentially associated with Early Onset Alzheimer's Disease susceptibility. NOTE: Due to the COVID-19 pandemic, we are currently completing large parts of these assessments through video conferencing (Zoom). Zoom is confidential and HIPPA compliant. Once the pandemic subsides we will resume in-person assessments.