Pediatric Agammaglobulinemia

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 by 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.

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 controls a person’s gender. This pair is 2 X chromosomes for females. The pair is one X and one Y chromosome for 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 before birth.

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.

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.

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

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) and chickenpox (varicella). This is because your child could develop the disease that the vaccine is meant to protect against.

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.

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 might be amniocentesis or chorionic villus sampling.

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.

Call the healthcare provider if your child has:

• Symptoms that don’t get better, or get worse
• Fever
• New symptoms