Hyper IgM (HIGM) syndrome is a rare immune disorder in which a child’s body doesn't produce certain disease-fighting antibodies. It is a primary immunodeficiency disease, which means it is inherited and present at birth.
There are two main types of hyper IgM, the most common of which – X-linked hyper IgM (XHIM) – only affects boys. The other form, autosomal recessive hyper-IgM syndrome (ARHIM) can affect both boys and girls.
Hyper IgM is the result of mutations to genes in the body's T cells, a type of white blood cell (lymphocyte). T cells control antibody production in the body's immune system. Antibodies are protein molecules that defend against harmful germs such as bacteria or viruses. Children with HIGM produce too many IgM antibodies and no IgG antibodies. XHIM results when a child inherits an abnormal gene from one parent. ARHIM occurs when a child inherits defective genes from both parents.
Children with HIGM are more susceptible to infections, have infections that won't go away or have recurrent severe infections. A child with HIGM is also more susceptible to certain cancers, including liver cancer. Symptoms of HIGM in children include
If your child is a boy and has recurrent, severe infections or doesn't respond well to treatments, see a doctor.
Hyper IgM (HIGM) syndrome is a disorder in which a child's immune system produces too many IgM antibodies while not producing any IgG antibodies. The result is that children can't fight off certain types of infections. Boys account for more than 70 percent of cases of HIGM, as the defective gene that causes the more common XHIM form attaches to the X chromosome.
Your child's doctor will begin a diagnosis by asking about your child’s medical history and performing a physical examination. If he suspects HIGM, he will send blood samples to a specialized lab for DNA testing. DNA tests confirm HIGM by analyzing the genes known to cause the disorder.
In most cases, Hyper IgM (HIGM) syndrome shows up in infancy. Nearly all cases are diagnosed by the time a child reaches 4 years of age. With proper treatment, children with HIGM can go on to lead normal, healthy lives.
The most common treatment for HIGM is intravenous immunoglobulin (IVIG) therapy. Children receiving this treatment get regular infusions of donated blood plasma to prevent infections. In boys with XHIM, IVIG replaces missing IgG antibodies while normalizing levels of IgM. Your child will receive IVIG infusions every three or four weeks for life. The treatments can be administered either at home or in an outpatient clinic. IVIG is the only effective treatment for ARHIM. Other treatments include:
Hyper IgM (HIGM) syndrome is a primary immunodeficiency disease (PIDD) that affects a child’s immune system. Around 70 percent of HIGM cases are defects on the X chromosome and only affect boys.
HIGM is extremely rare. Seventy percent of the most common form (XHIM) is passed on from the child’s mother. The remaining 30 percent come from new mutations.
Due to the mutation, a child with HIGM produces too much of the IgM antibody and none of the IgG antibody. A mother with the defective gene will pass XHIM -- the most common form of the disorder -- to a male child.
Children with HIGM are susceptible to chronic, hard to treat bacterial infections. Symptoms include recurrent sinusitis, ear or eye infections and pneumonia.
Your child’s doctor will ask you about your child’s symptoms and send a blood sample to a special lab for genetic testing. DNA tests will confirm HIGM.
The most common treatment for HIGM is intravenous immunoglobulin therapy. Other treatments include antibiotics for infections and either bone marrow or stem cell transplants.
Children with HIGM who receive proper treatment usually lead normal, healthy lives. Without treatment, children may develop serious diseases such as liver cancer.