Agammaglobulinemia (AGMX) is an inherited immune system disorder. Passed from parent to child, it is also known as Bruton’s agammaglobulinemia, congenital agammaglobulinemia, and X-linked agammaglobulinemia. AGMX was one of the first immune system diseases identified.
People with AGMX have trouble making antibodies. This makes it more difficult for them to fight infection. Antibodies play a major role in the immune system’s defense against disease.
AGMX is passed from parent to child children. A gene abnormality on the X chromosome interferes with the body’s ability to produce antibodies. The gene is known as Bruton’s Tyrosine Kinase (BTK). It was identified in 1993.
AGMX occurs far more often in men than in women. This is because the mutation that causes it is on the X-chromosome. Men only have one X-chromosome. Therefore, a single defective copy of the gene can cause the condition. This is known as X-linked inheritance.
Women have two X-chromosomes. That makes it possible for them to be carriers of AGMX. In women, a normal copy of the gene can mask problems caused by the mutation. Both of a woman’s parents have to pass on an AGMX mutation for her to have AGMX.
There have been families where AGMX did not follow an X-linked pattern. This may have been due to a new X-chromosome mutation. The families may also have been too small to detect the pattern.
The immune system uses antibodies to recognize and fight infections. Children are protected by their mother’s antibodies during the first six months of their life. After six months, a child must produce their own antibodies. However, children with AGMX are unable to. This leaves them susceptible to disease
The gene that causes AGMX affects pre-B-lymphocyte maturation. The cells do not develop properly into antibody producing cells.
Symptoms of AGMX usually appear when children are between 6 and 9 months old. However, some children do not have symptoms until they are between 3 and 5 years old. Boys are generally affected at an earlier age.
Symptoms of AGMX include:
- gastrointestinal infections, including chronic diarrhea
- viral infections from viruses such as polio and hepatitis
- nasal infections
- eye infections
- blood stream infections
- lung infections
- skin infections
- bone infections
- bronchial infections
- spinal cord infections
- ear infections
- kidney inflammation
- joint disease
- breakdown of red blood cells
- muscle and skin inflammation
- reduced number of neutrophils in the blood
- failure to grow
- blood or colon cancer (rare)
Many of the above conditions also occur in children without AGMX. However, children with AGMX get sick more frequently. They may also have more severe symptoms.
To diagnose AGMX, your child’s doctor will need a complete medical history. He will also perform a physical examination. Blood samples will be taken to look for immune system problems.
Various tests can be used to determine the antibody levels in your child’s blood. These include flow cytometry, quantitative immunoglobulins, and immunoelectrophoresis.
AGMX treatment depends on a number of factors. Your child’s age, overall health, and medical history will be taken into account. So will the severity of the condition. One common form of treatment is intravenous antibody replacement. Antibodies are infused directly into the bloodstream to help stop infections. This is also known as gamma globulin therapy.
If your child has AGMX, there are other things you should be aware of. Children with AGMX should always seek immediate treatment for any infection or illness. They should also avoid live viral vaccinations. In a child with AGMX, a live vaccine could cause the disease instead of helping prevent it.
Children with AGMX can live healthy lives. They can even participate in normal activities, including sports. However, it is important for them to be diagnosed early and treated successfully.
AGMX can be fatal when left untreated. Without antibodies, children have no protection against serious infections.
Even with treatment, children with AGMX may have shortened lives. Chronic lung disease can sometimes cause irreversible damage to their lungs.
Doctors recommend genetic counseling for families with a history of AGMX. Women who know that they are carriers can have an amniocentesis or chorionic villus sampling while pregnant to check for this condition. The chance of passing the abnormal gene to a child is 50 percent.