Babies with XLA generally appear healthy for the first few months because they're protected by the antibodies they got from their mothers before birth. When these antibodies clear from their systems, the babies begin to develop often severe, recurrent bacterial infections — such as of the ears, lungs, sinuses and skin — that can be life-threating.

Male infants born with XLA have:

• Very small tonsils
• Small or no lymph nodes

X-linked agammaglobulinemia is caused by a genetic mutation. People with the condition can't produce antibodies that fight infection. About 40% of people with the condition have a family member who has it.

People with XLA can live relatively normal lives and should be encouraged to participate in regular activities for their ages. However, recurrent infections related to XLA will likely require careful attention and aggressive treatment. They can cause organ damage and be life-threatening.

Possible complications include:

• Chronic lung disease
• Increased risk of certain cancers
• Infectious arthritis
• Increased risk of central nervous system infections from live vaccines

Your doctor will take a medical history to document recurrent infections and do a physical exam. He or she will order blood tests and possibly recommend genetic testing to confirm the diagnosis.

There's no cure for XLA. The goal of treatment is to boost the immune system, preventing infections and aggressively treating infections that occur.

Medications

Medications to treat XLA include:

• Gammaglobulin. This is a type of protein found in blood that contains antibodies against infections. It's given by infusion into a vein every two to four weeks or by weekly injection.

  Reactions to gammaglobulin can include headache, chills, backache and nausea. Reactions are more likely to occur during a viral infection.

• Antibiotics. Some people with XLA receive continuous antibiotics to prevent infections. Others take antibiotics for bacterial infections longer than people without XLA do.

Your doctor will likely recommend that you have follow-up visits every six to 12 months to screen for complications of XLA. You'll also likely be advised to not get live vaccines, such as live polio, measles-mumps-rubella or chickenpox vaccines.