Trisomy 21 mosaicism has been found in women who developed a

Trisomy 21 mosaicism has been found in women who developed alzheimers at age 40, although they were not characterized as having down\'s sydrome. The amyloid precursor protein (APP) resides on chromosme 21.

How did this mosaicism arise?

Why might Alzheimer\'s disease have developed so early?

Solution

Answer= the alzheimers disease is a protein misfolding disease

Caused by plaque accumulation of abnormally folded beta amyloid protein

Amyloid beta is a fragment from amyloid precursor protein (APP)

App is transmembrane protein that penetrates through neurons membrane

Gamma secretase & beta secretase acts on APP & divided into smaller fragments

One of these fragments gives rise to fibrils of amyloid beta which then forms clumps that deposite outside the neurons in dense formation known as senile plaque & forms a mosaicism

Alzheimers developed so early =

People inherit rare genes that directly cause alzeimers

caused by deteriministic genes

They have inherited changes in 3 genes