Deciphering the mechanism that underlies the development of Alzheimer's disease in certain families but not in others, researchers at the Hebrew University of Jerusalem's Faculty of Medicine have proposed that the malady is actually a collection of diseases that probably should be treated with a variety of different approaches.
Neurodegenerative diseases are incurable and debilitating conditions that result in degeneration or death of cells in the nervous system. Conditions such as prion disorders (the most famous of which is "Mad Cow Disease"), Alzheimer's Disease and Parkinson's Disease share two key features: they emerge as a result of aberrant protein folding and aggregation, and their onset is late in life. These maladies emerge either sporadically or as familial, mutation-linked illnesses (certain prion disease can be also infectious).
Most sporadic cases are diagnosed during the patient's seventh decade of life or later, while familial cases typically manifest during the fifth or sixth decade. Despite their relative rareness, mutation-linked cases are very important, as they provide hints that can help decipher the mechanisms that underlie the development of the disease.
The late onset feature typical to distinct neurodegenerative diseases, and the common temporal emergence patterns of these maladies, raise key questions: first, why do individuals who carry disease-linked mutation show no clinical signs until their fifth or sixth decade of life? In addition, why do apparently distinct disorders share a common temporal emergence pattern?
One possible explanation is that as people age, the efficiency of the mechanisms that protect younger people from the toxic aggregation of proteins declines, thus exposing them to disease. Indeed, previous studies clearly indicate that the aging process plays key roles in enabling neurodegenerative disorders to onset late in life.