Chromosome Parade #1: Presenilin 2 Gene

Every Saturday, I’m planning to highlight a disease gene on each of the 24 human chromosomes: 1-22, X, and Y. My resource will be the Genetics Home Reference and I’ll choose whatever catches my eye for the chromosome of the week.

This week, I’m checking out the PSEN2 gene on the long arm of chromsome 1 (1q31-q42). I’ve written about the presenilin genes before and here’s an excerpt from the Genetics Home Reference:

Approximately 11 mutations in the PSEN2 gene have been shown to cause type 4 Alzheimer disease. Mutations in this gene account for less than 5 percent of cases of early-onset familial Alzheimer disease. Two of the most common PSEN2 mutations that cause type 4 Alzheimer disease change one of the building blocks (amino acids) used to make presenilin 2. …These mutations appear to affect the processing of amyloid precursor protein, leading to the increased formation of a protein fragment called amyloid beta peptide. This peptide can form clumps in the brain (amyloid plaques) that are characteristic of Alzheimer disease.

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