What is X-linked agammaglobulinemia in children?

X-linked agammaglobulinemia is a rare genetic disease. It causes a weakened immune system. It is also known as Bruton's agammaglobulinemia. X-linked means that the gene that causes this disease is located on the X chromosome. It mainly affects boys because they have only have one X chromosome.

A child with this disease can’t make antibodies that are part of gamma globulins in blood plasma. Antibodies are the body's main defense against germs like bacteria and viruses. So a child with this disease can’t fight off infections caused by bacteria and some viruses.

Boys with this disease are more likely to get infections in the middle ear, sinuses, and lungs. The infections can also involve the bloodstream or internal organs. Most children with this disease who are treated early can lead normal, active lives.

What causes X-linked agammaglobulinemia in a child?

X-linked agammaglobulinemia is caused by a faulty gene on the X chromosome. People normally have 23 pairs of chromosomes in each cell of their body. The 23rd pair generally determines the assigned sex of a person at birth. This pair is two X chromosomes for biological females. The pair is one X and one Y chromosome for biological males.

Girls can have the faulty gene on one of their X chromosomes but not have any symptoms of the disease. They are carriers for the condition. Boys have only one X chromosome. If their X chromosome carries a faulty gene, they will have symptoms.

In some cases, a child may have the faulty gene without inheriting it. This can happen if there is a new change (mutation) on the child’s X chromosome at the time of conception.

Which children are at risk for X-linked agammaglobulinemia?

Women who are carriers have a 1 in 2 chance of passing the faulty X chromosome to a child. This is true for every pregnancy. If a daughter gets the gene, she will likely be a healthy carrier like her mother. If a son gets the gene, he will have X-linked agammaglobulinemia.

What are the symptoms of X-linked agammaglobulinemia in a child?

The symptoms of this disease usually show up in the first 6 to 9 months of age. But they can also show up as late as age 3 to 5 years.

Common symptoms include:

• Many serious or life-threatening illnesses, such as infections of the nasal passages, skin, eyes, bones, lungs, digestive tract, and bloodstream

• Failure to grow

• No tonsils or adenoids

• Joint disease, mainly in the knees, similar to juvenile rheumatoid arthritis

• Breakdown of red blood cells (autoimmune hemolytic anemia)

• Kidney inflammation (glomerulonephritis)

• Fewer white blood cells called neutrophils (neutropenia)

• Skin and muscle inflammation (dermatomyositis)

A few older children with this disease may have cancers such as leukemia, lymphoma, or colon cancer.

The symptoms of this disease may be like other health conditions. Make sure your child sees their healthcare provider for a diagnosis.

How is X-linked agammaglobulinemia diagnosed in a child?

The healthcare provider will ask about your child’s symptoms and health history. They may also ask about your family’s health history. The provider will give your child a physical exam. Your child may need many blood tests to help confirm the diagnosis.

How is X-linked agammaglobulinemia treated in a child?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

Treatment may include:

• Replacing antibodies. This treatment gives your child the antibodies that they can’t make. This protects your child against infections. It also helps stop infections from spreading.

• Treating and preventing infections. The healthcare provider will treat any infections right away. Or the healthcare provider may give your child antibiotics before they have an infection.

• Not getting live virus vaccines. This includes vaccines for measles, mumps, rubella (MMR), rotavirus, smallpox and chickenpox (varicella). This is because your child could develop the disease that the vaccine is meant to protect against.

What are possible complications of X-linked agammaglobulinemia in a child?

Without antibody replacement, a child with this disease could die at an early age from severe infections. Some children who get chronic lung disease with widening and scarring of the airways (bronchiectasis) may have a shortened lifespan. But most children with X-linked agammaglobulinemia who are treated early can lead normal, active lives.

What can I do to prevent X-linked agammaglobulinemia in my child?

Think about getting genetic testing and counseling if X-linked agammaglobulinemia runs in your family. A woman can get tested for the gene. If you are a known carrier, you can also have prenatal testing to find out if your child has inherited the gene. This testing might occur through an amniocentesis or chorionic villus sampling.

How can I help my child live with X-linked agammaglobulinemia?

Most children with X-linked agammaglobulinemia who are treated early can lead normal, active lives. Be sure to:

• Keep all appointments with your child’s healthcare provider.

• Call your child’s healthcare provider if you are concerned about your child’s symptoms

• Practice good infection prevention habits, such as handwashing and keeping your child away from others with infections.

• Tell others of your child’s condition. Work with your child’s healthcare provider and school to come up with a treatment plan.

When should I call my child’s healthcare provider?

Call the healthcare provider right away if your child has:

• Symptoms that don’t get better, or get worse

• Fever

• New symptoms

Key points about X-linked agammaglobulinemia in children

• X-linked agammaglobulinemia is a rare genetic disease. It causes a weakened immune system and difficulty fighting infections.

• Boys are affected more often than girls.

• Most children with this disease who are treated early can lead normal, active lives.

• Treatment may include replacing antibodies, treating and preventing infections, and not getting live virus vaccines.

• A woman can get tested for the gene. If you are a known carrier, you can also have prenatal testing to find out if your child has inherited the gene. This might be amniocentesis or chorionic villus sampling.

• Keep in regular touch with your child’s healthcare provider, and tell your child’s school and other close contacts. This will help your child stay healthier.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.