Genes and Possible Environmental Triggers

Genes are instructions passed down from your parents. Some versions of certain genes raise type 1 risk, and some lower it.

The best-known group is HLA genes. Your immune system is your body's defense team. HLA genes help that team tell your own cells from invaders.

A risk version is like a loose latch on a gate. It raises the odds, but it does not decide alone.

A close relative with type 1 can raise your risk. For people in general, the chance over a whole life is about 0.4 percent. A brother or sister's chance is about 6 to 7 percent.

Still, most people with type 1 have no close relative with the disease. Most people with risk gene versions never develop it.

Researchers are still studying environmental triggers. These are outside factors, such as viruses.

One group being studied is enteroviruses, a family of common viruses. Several studies link them to the start of the immune attack.

No single trigger is proven for all cases.

Key takeaways

• Certain gene versions raise the chance of type 1, but they do not decide it alone.
• A close relative raises risk, yet most people with risk genes never develop type 1.
• Environmental triggers are still being studied, and no single cause is proven for all cases.

Try it

List any close relatives you know of who have type 1, and how each one is related to you. Write down one question about your own risk to bring to your next visit.