Alzheimer's
A disease most commonly found in the older generation of people causing them to lose pre-existing memories and have trouble making new ones. More serious cases can lead to difficulty with language, disorientation, mood swings, etc.
Example:
Lil' Jimmy: "Mama, why doesn't Grandpa remember me?"
Mama: "He's got Alzheimer's, Honey, he won't remember you."
Lil' Jimmy: "Oh... Will Grandma get Old-Timer's too then?"
Lil' Jimmy: "Mama, why doesn't Grandpa remember me?"
Mama: "He's got Alzheimer's, Honey, he won't remember you."
Lil' Jimmy: "Oh... Will Grandma get Old-Timer's too then?"