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What causes primary immunodeficiency?

Primary immunodeficiency (PI) is caused by genetic mutations that affect how your immune system works. These genetic changes are usually inherited from your parents, which is why many people with PI have a family history of the condition.

The mutations are present at birth, even if Show Full Answer

What causes primary immunodeficiency?

Primary immunodeficiency (PI) is caused by genetic mutations that affect how your immune system works. These genetic changes are usually inherited from your parents, which is why many people with PI have a family history of the condition.

The mutations are present at birth, even if symptoms don't show up until later in life. This is what makes PI "primary" — the problem is built into how your body was made from the start.

Common types of genetic mutations that cause PI include:

* Mutations affecting antibody production by B cells
* Changes that prevent proper development of immune cells
* X-linked mutations (passed through the X chromosome, affecting males more often)
* Mutations affecting T-cell function

In rare cases, PI can develop from genetic changes that happen after birth rather than being inherited. These are called phenocopies and make up less than 1 percent of all PI cases.

It's important to distinguish PI from secondary immunodeficiency, which develops later in life from outside factors like medications, infections, or other medical conditions — not from inherited genetic mutations.

 AI-generated responses are not a substitute for medical advice. These services are not intended to diagnose, treat, or cure any condition or disease. Always ask your doctor about specific health concerns.

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