Some Types of PI:

Hyper-IgM Syndromes (HIGM)

People with HIGM syndrome have normal or high levels of immunoglobulin M (IgM) in their blood, but reduced levels of other immunoglobulins, including IgG, IgA, and IgE. This imbalance can lead to recurrent and severe infections. HIGM syndrome is one of more than 400 different types of primary immunodeficiency (PI).

The most common form of HIGM syndrome is passed along as an X-linked recessive trait (XHIGM) and is usually found only in boys. However, other forms of HIGM syndrome are inherited by both boys and girls as autosomal recessive traits.

There are over 450 different types of PI, each with its own characteristics and challenges.
Need a crash course? Learn the basics of PI.

How is a trait inherited?

Some conditions are caused by mutations in a single gene and can be inherited from one or both parents.

HIGM syndrome is genetic, and is usually passed down in one of two ways:

X-linked recessive inheritance comes from a mutation in a gene on the X chromosome and is passed through the mother. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition, which is why HIGM syndrome mainly affects males. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder
Autosomal recessive inheritance is passed through numbered chromosomes (autosomal, 1-22) as opposed to sex chromosomes (X or Y), so it’s not specific to gender. In this type of inheritance, both parents (typically without the condition) carry a copy of the mutated gene

Symptoms of hyper-IgM syndrome (HIGM)

Most children with HIGM syndrome will develop symptoms within the first or second year of life. The most common HIGM syndrome symptoms are:

An increased risk of infection, including repeated upper and lower respiratory tract infections. Most infections are bacterial, but they can also be viral
Gastrointestinal issues, including diarrhea and difficulty absorbing nutrients from food (malabsorption)
Pneumocystis jiroveci, an opportunistic form of pneumonia, in the first year of life
Susceptibility to cryptosporidium that may lead to disease of the liver
Low white blood cell count (neutropenia). In severe cases, this is associated with mouth ulcers, inflammation, ulceration of the rectum, and skin infections
Increased likelihood to experience enlargement of the lymph nodes and the spleen. That means it’s not unusual for people with HIGM syndrome to have enlarged tonsils and adenoids – which can cause snoring and obstructive sleep apnea
Occurrence of an autoimmune disorder, in which a person's immune system attacks the body
Increased risk of cancer, particularly of the liver

Diagnosis of hyper-IgM syndrome (HIGM)

When someone experiences severe recurrent respiratory infections, or an opportunistic infection, a doctor might screen for HIGM. If blood tests show a normal or elevated level of IgM and low or absent IgG, with normal T cell and B cell numbers, genetic testing is needed. Final diagnosis is based on an analysis of the person's DNA to identify mutations in genes known to cause HIGM syndrome.

What should I know about treatment for hyper-IgM syndrome (HIGM)?

You are not alone, but no one is quite like you. It's important to learn about the various treatments for PI, and should be individualized to meet your specific needs. Your healthcare team is there to provide recommendations based on you, and your situation. Here are some tips:

Keep track of how you’re doing and share the information with your doctor on a regular basis.
Your doctor will only know how you’re doing if you tell them. If you have questions, concerns, thoughts or feelings—speak up and share!
You and your doctor both play a part in managing your health. You can take an active role by learning as much as you can and by following your doctor’s recommendations.