- Our Story - In Memory CAF's Dr. Tanzi on the latest on
Alzheimer's Disease Genes The Four Known Alzheimer’s Genes Over
the past several decades, it has become increasingly clear that
inheritance plays a major role in Alzheimer’s disease. The
roughly 25,000 genes in the human genome are comprised of
deoxyribonucleic acid (DNA) packaged into 24 different
chromosomes, 1-22, X and Y. A gene’s job is to either make
proteins or control the activity of other genes. Over many
generations, the DNA of a gene can mutate to create a “variant”.
A very rare DNA variant is called a “mutation”, while a variant
that is common in the population is called a “polymorphism”. DNA
variants allow for all of us to be a little different from each
other. There are about 3 million variants that differ between
any two individuals. Variants in certain genes can directly
cause a disease like Alzheimer’s, can increase susceptibility to
disease, or can even confer protection against disease. One’s
risk for most age-related diseases such as