The study will test LX1001, which is also called AAVrh.10hAPOE2. LX1001 is a new investigational drug that is being developed for treating people like you with AD. It is not approved, by health authorities such as the US Food and Drug Administration (FDA), for treating AD. It can only be used in a study like this one. It belongs to a group of drugs known as gene therapy which is a form of therapy that involves the insertion of one or more corrective genes that have been designed in the laboratory to cure a disease. This study is the first time that LX1001 will be given to humans.