Familial Polyposis Coli (FAP) is caused by changes in the APC gene. This gene, we know, plays a role in guiding cells during gut development. Infact, every body cell in our body receives instructions during development so that the right type of cell is created in the right place. A bowel cell in the intestinal wall has certain properties that are necessary for a proper function of the intestine. A cell in the renal cortex looks different again and therefore has other functions that are important for the kidneys. Those instructions are coded in our genes. APC is one of an estimated 21,000 genes in our human DNA and its function is to give specific instructions to the developing intestinal cells. A change in the APC gene ("mutation") can cause a change in these instructions, such that intestinal cells are inclined to develop in a different way which causes the formation of polyps; the hallmark of FAP.

Over the past years, there are findings from various studies that indicate that the APC gene not only performs an organizing function in the intestines, but also in the brain. Although we already know that there are no increased rates of polyps in the brains of people with FAP, the question can still be asked if a mutation in the APC gene can affect brain development and function in a more subtle way. It’s good to be aware of the fact that part of what makes us unique as a human individual is how our brain works.

Differences between brains are the consequence of subtle variations in how our brains are wired, guided by genetic instructions as well as the experiences we have during our life. This said, if the APC gene influences the wiring of our brain, we can expect that a group of people that all share a mutation in the same APC gene may also experience the same (subtle) differences in brain function. How can we find out if this is the case? One way would be to ask individuals with FAP about how things are going in school,  with friends and at home and then ask the same questions at siblings without FAP. Comparing the results will help us understand the possible effects of APC on the brain. This, in essence, what we are trying to do with our study “Behavior and Cognition in APC”.