Alzheimer's and Alzheimer's disease

Alzheimer's noun - A progressive form of presenile dementia that is similar to senile dementia except that it usually starts in the 40s or 50s; first symptoms are impaired memory which is followed by impaired thought and speech and finally complete helplessness.

Alzheimer's disease and Alzheimer's are semantically related. In some cases you can use "Alzheimer's disease" instead a noun "Alzheimer's".

Alzheimer's disease noun - A progressive form of presenile dementia that is similar to senile dementia except that it usually starts in the 40s or 50s; first symptoms are impaired memory which is followed by impaired thought and speech and finally complete helplessness.

Alzheimer's and Alzheimer's disease are semantically related. You can use "Alzheimer's" instead a noun phrase "Alzheimer's disease".