Common disease-common variant

Okay, so sometimes our bodies can get sick because there are things called "disease-causing genes" that we have inherited from our parents. These genes can make us more likely to get certain diseases, like diabetes or cancer.

Now, a "common variant" is a gene that many people have, and it doesn't always cause disease. It's like having brown eyes or blonde hair - lots of people have those things too, but they're not bad for your health.

When we talk about "common disease-common variant", we mean that there are certain genes that are very common in lots of different people, and also happen to increase the risk of getting certain diseases.

For example, there is a common variant called "APOE4" that lots of people have. But having this variant also increases the risk of getting Alzheimer's disease later in life.

Scientists study these common variants to try to figure out why certain people are more likely to get sick than others. And if we can understand why these common variants are linked to certain diseases, we might be able to find ways to prevent or treat those diseases in the future.