Reviewed December 2008
What is the official name of the PSEN2 gene?
The official name of this gene is “presenilin 2 (Alzheimer disease 4).”
PSEN2 is the gene's official symbol. The PSEN2 gene is also known by other names, listed below.
What is the normal function of the PSEN2 gene?
The PSEN2 gene provides instructions for making a protein called presenilin 2. Presenilin 2 helps process proteins that transmit chemical signals from the cell membrane into the nucleus. Once in the nucleus, these signals turn on (activate) genes that are important for cell growth and maturation.
Presenilin 2 is best known for its role in processing amyloid precursor protein, which is found in the brain and other tissues. Research suggests that presenilin 2 works together with other enzymes to cut amyloid precursor protein into smaller segments (peptides). One of these peptides is called soluble amyloid precursor protein (sAPP), and another is called amyloid beta peptide. Recent evidence suggests that sAPP has growth-promoting properties and may play a role in the formation of neurons in the brain both before and after birth. Other functions of sAPP and amyloid beta peptide are under investigation.
How are changes in the PSEN2 gene related to health conditions?
Alzheimer disease - caused by mutations in the PSEN2 gene
At least 11 mutations in the PSEN2 gene have been shown to cause early-onset Alzheimer disease. Mutations in this gene account for less than 5 percent of all early-onset cases of the disorder.
Two of the most common PSEN2 mutations that cause early-onset Alzheimer disease change single protein building blocks (amino acids) used to make presenilin 2. One mutation replaces the amino acid asparagine with the amino acid isoleucine at position 141 (written as Asn141Ile or N141I). The other mutation changes the amino acid methionine to the amino acid valine at position 239 (written as Met239Val or M239V). These mutations appear to disrupt the processing of amyloid precursor protein, leading to the overproduction of amyloid beta peptide. This protein fragment can build up in the brain and form clumps called amyloid plaques that are characteristic of Alzheimer disease. A buildup of toxic amyloid beta peptide and amyloid plaques may lead to the death of neurons and the progressive signs and symptoms of this disorder.
Where is the PSEN2 gene located?
Cytogenetic Location: 1q31-q42
Molecular Location on chromosome 1: base pairs 225,125,585 to 225,150,421
The PSEN2 gene is located on the long (q) arm of chromosome 1 between positions 31 and 42.
More precisely, the PSEN2 gene is located from base pair 225,125,585 to base pair 225,150,421 on chromosome 1.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about PSEN2?
You and your healthcare professional may find the following resources about PSEN2 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
What other names do people use for the PSEN2 gene or gene products?
- AD3-like protein
- Alzheimer's disease 3-like
- PS2 protein (alzheimer-associated)
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding PSEN2?
The resources on this site should not be used as a substitute for
professional medical care or advice. Users seeking information about
a personal genetic disease, syndrome, or condition should consult with a qualified
See How can I find a genetics professional in my area? in the Handbook.