The purpose of this study is to identify genetic factors that contribute to or cause dementia (loss of memory) and related disorders across all ages and ethnic groups. This includes a number of neurological diseases such as early and late-onset Alzheimer disease, mild cognitive impairment, and other dementias.

Inclusion Criteria:

1. 18 years and older
2. Patients diagnosed with dementia, their family members and unrelated healthy controls without dementia.

Exclusion Criteria:

1. Individuals with competing diagnosis such as: Amyotrophic lateral sclerosis, Frontotemporal lobar degeneration, Multiple system atrophy, Corticobasal degeneration, Progressive Supranuclear Palsy, Huntington's disease, traumatic brain injury, drug or alcohol abuse, or schizophrenia, etc. (unless family members of a dementia affected individual).

The study population consists of older individuals affected by dementia, mild cognitive impairment, cognitive controls, or their family members. Ascertainment is across both males and females, and all race-ethnic groups.

Data from this study will be shared via government required repositories and with our collaborators. Data are coded, with no personally identifiable information included. Data shared include the genomic data (array data, sequence data, APOE genotyping results, etc), phenotype data (case/control status, age of onset, etc), and basic demographic information (sex, race/ethnicity data if available, etc).

The NIH Genomic Data Sharing Policy (GDS Policy) took effect on January 25th, 2015. This necessitates that we send coded data and samples to the National Institute on Aging Genetics of Alzheimer's Disease (NIAGADS)l; in some cases materials derived from participants (blood or DNA) may be stored at the National Cell Repository for Alzheimer's Disease (NCRAD).

We may share deidentified genomic and phenotypic data with collaborators at other sites in order the accomplish the scientific aims of the study. Such research is performed with the approval of the local internal review boards.

This study adheres to the NIA Alzheimer Disease Genomics Data Sharing Plan (https://www.nia.nih.gov/research/dn/alzheimers-disease-genomics-sharing-plan). As such, genomic data will be deposited in NIH/NIA data repositories (www.niagads.org). For genomic data, this typically happens within a year of data generation, or upon publication in scientific journals (whichever is sooner). Basic phenotypic data (affection status, age of onset, sex, family structure if applicable, etc) are deposited with the genomic data. More detailed phenotypic data (cognitive data, biomarker, etc) will be made available upon publication. Data dictionaries for primary data (genomic data and basic phenotypic data) will be available with the deposition of data into the NIH/NIA data repositories (www.niagads.org). Additional supporting documentation (analysis plans, study protocols, etc) is typically described in detail upon publication of results in peer reviewed literature.

This study adheres to the NIA Alzheimer disease Genomics Data Sharing Plan (https://www.nia.nih.gov/research/dn/alzheimers-disease-genomics-sharing-plan). As part of this plan data distribution agreements are required before recipients receive any data from this study. The primary requirements for the DDA include language ensuring that (1) data are not transferred to others beyond the initial recipient, (2) no attempt will be made to identify participants, (3) any results or data generated as part of the study will be shared back to NIA/NIAGADS. See the NIA Data Distribution Agreement for more details (https://www.niagads.org/sites/all/public\_files/NIAGADS-DDA.pdf).