A Study of Crenezumab Versus Placebo in Preclinical Presenilin1 (PSEN1) E280A Mutation Carriers to Evaluate Efficacy and Safety in the Treatment of Autosomal-Dominant Alzheimer's Disease (AD), Including a Placebo-Treated Non-Carrier Cohort

Inclusion Criteria

• Membership in PSEN1 E280A mutation carrier kindred
• Agrees to conditions of, and is willing to undergo, genetic testing (for example [e.g.], apolipoprotein E [APOE], PSEN1 E280A, and other genetic testing)
• PSEN1 E280A mutation carrier or non-carrier status has been confirmed prior to or during the screening period
• Mini-Mental Stage Examination (MMSE) greater than or equal to (>=) 24 for participants with less than ( =26 for participants with 9 or more years of education
• Does not meet criteria for dementia due to AD per the National Institute on Aging and the Alzheimer's Association Workgroup (McKhann et al. 2011) criteria
• Does not meet criteria for mild cognitive impairment (MCI) due to AD per the National Institute on Aging and the Alzheimer's Association Workgroup (Albert et al. 2011) criteria
• Adequate vision and hearing in the investigator's judgment to be able to complete testing
• If female, and not documented (by medical records or physician's note) to be surgically sterile (absence of ovaries and/or uterus) or postmenopausal, willing to undergo pregnancy tests at protocol-specific timepoints
• For women who are not documented (by medical records or physician's note) to be surgically sterile (absence of ovaries and/or uterus) or postmenopausal, agreement to remain abstinent or use two adequate methods of contraception, including at least one method with a failure rate of =2 years prior to screening
• History of severe, clinically significant (persistent neurological deficit or structural brain damage) central nervous system trauma (e.g. cerebral contusion)
• Body weight 120 kilograms (kg)
• History or presence of atrial fibrillation that poses a risk for future stroke in the investigator's judgment
• Clinically significant laboratory or ECG abnormalities (e.g., abnormally prolonged or shortened QTc interval) in the investigator's judgment
• Current presence of bipolar disorder or other clinically significant major psychiatric disorder according to Diagnostic and Statistical Manual of Mental Disorders 4th Edition Text Revision (DSM-IV-TR) or symptom (e.g., hallucinations, agitation, paranoia) that could affect the participant's ability to complete evaluations
• Clinically significant depression, based in part by a Geriatric Depression Scale (short form) (15-point scale) score >9 at screening
• History of seizures (excluding febrile seizures of childhood, or other isolated seizure episodes that were not due to epilepsy in the judgment of the investigator, and required at most time-limited anticonvulsant treatment, and which occurred more than 7 years prior to the screening visit)
• Myocardial infarction within 2 years, congestive heart failure, atrial fibrillation, or uncontrolled hypertension
• Pregnant or nursing women, or women who intend to become pregnant or to nurse infants during the conduct of this trial
• Clinically significant infection within the last 30 days prior to screening
• Positive urine test for drugs of abuse at screening
• History of alcohol or substance dependence within the previous two years
• Use of any other medications with the potential to significantly affect cognition; intermittent or short-term use of these medications may be allowed if deemed medically necessary for the treatment of a non-excluded medical condition with approval from the Medical Monitor. In addition, use of tricyclic antidepressants or benzodiazepines will be permitted if used in stable, low doses for the treatment of a non-excluded medical condition with approval from the Medical Monitor
• Use of typical anti-psychotics or barbiturates
• Use of non-anti-cholinergic antidepressant medications or atypical anti-psychotics unless maintained on a stable dose regimen for at least 6 weeks prior to screening
• Use of any Food and Drug Administration (FDA)/Instituto Nacional de Vigilancia de Medicamentos y Alimentos (INVIMA)-approved medications for treatment of late onset Alzheimer's disease (LOAD)