X-linked agammaglobulinemia (Bruton disease)

What happens in this disease?

B cells are white blood cells that make antibodies. Antibodies mark germs so that they can be destroyed. In this disease, the BTK gene is faulty, so B cells cannot develop. The body makes very few antibodies and becomes open to infections.

Which symptoms can occur?

Babies are protected for the first 1-2 months by antibodies passed on from the mother. Then repeated infections begin.

• Pneumonia and bronchitis (common)
• Ear and sinus infections (common)
• Eye infections (common)
• Long-lasting diarrhea
• Infections that heal slowly and come back often
• Swelling and pain in the joints
• Some viral infections being severe

How is it diagnosed?

Antibody levels in the blood are measured, and all are found to be very low. The number of B cells in the blood is checked; there are very few B cells. The diagnosis is confirmed with a genetic test showing the change in the BTK gene.

Treatment and care

The main treatment is regularly replacing the missing antibodies. This treatment is given through a vein or under the skin. It reduces infections and improves quality of life. Infections are treated with antibiotics. Sometimes preventive antibiotics are also given. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

The disease is passed on through X-linked recessive inheritance and almost always affects males. A mother who is a carrier has a 1 in 4 chance of having an affected boy in each pregnancy. Women who are carriers have no immune problems. All daughters of an affected father become carriers, while his sons are not affected. In about half of patients, no one else in the family is affected. Genetic counselling guides the family.