Some Types of PI:

DiGeorge Syndrome (DGS)

DiGeorge Syndrome (DGS), also known as 22q11.2 deletion syndrome, is a type of PI caused by abnormal cell and tissue development during fetal growth. DiGeorge Syndrome is one of over 400 different types of PI. Often, but not always, people with DGS are susceptible to infections due to poor T-cell production and function.

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

What’s a T cell?

The immune system is made up of specialized cells and proteins. These include white blood cells called lymphocytes.

A T cell is a lymphocyte and comes in 4 types, each with a special purpose:

Helper T cells detect infection and get the other cells of the immune system ready for battle. Helper T cells also tell B cells to produce antibodies, highly specialized proteins that help defend the body against infection.

Cytotoxic, or killer, T cells destroy infected cells.

Regulatory T cells tell the immune system when the battle with the pathogens is over and to stop fighting.

Memory T cells remember how to defeat an infection and can respond rapidly if the same infection recurs.

Symptoms of DiGeorge Syndrome (DGS)

People with DGS may have any or all of the following:

Distinct facial appearance: Children may have an underdeveloped chin, eyes with heavy eyelids, ears that are rotated back, and defective upper portions of their earlobes
Parathyroid gland abnormalities: An underdeveloped parathyroid gland may cause hypoparathyroidism, leading to difficulty maintaining normal levels of calcium, which may cause seizures or convulsions. A parathyroid problem often becomes less severe over time
Thymus gland abnormalities: Underdevelopment or incomplete development of the thymus gland results in a smaller-than-normal-sized thymus and decreased production of T lymphocytes, or T cells. Not only do T cells destroy infected cells, but they also help B lymphocytes (B cells) develop into plasma cells that produce immunoglobulins, or antibodies. A lack of T cells results in an increased risk of viral, fungal, and bacterial infections
Autoimmunity: People with DGS may develop an autoimmune disease, which occurs when the immune system attacks its own body

Other clinical features: Some people with DGS have learning disabilities, behavioral problems, psychiatric disorders, and/or hyperactivity. They may also have other developmental abnormalities, including:

Cleft palate
Poor function of the palate
Delayed speech
Difficulty eating and swallowing

Diagnosis of DiGeorge syndrome

DGS diagnosis is often made on the signs and symptoms present at birth or that develop soon after birth. The diagnosis can usually be confirmed with genetic tests. The most common cause of DGS is due to a deleted section of chromosome 22. The small proportion of patients without the genetic defect are diagnosed based on clinical features and by excluding a diagnosis of other syndromes.

Traditionally, DGS was diagnosed when a person had the characteristics described above. However, people with DGS differ not only in the organs and tissues affected, but also in terms of how severely the organ or tissue is affected. This meant that many mild cases were missed when diagnosis relied on symptoms alone.

What should I know about treatment for DiGeorge syndrome?

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.