Genetic Testing for People with Primary Immunodeficiencies

If you are living with a primary immunodeficiency (PID), including neutropenia, you and your doctors may have spent a lot of time—using trial and error—to understand your symptoms and possible treatments. You may have been misdiagnosed or even still feel that you haven’t found the right diagnosis.

Now, diagnostic genetic testing may give you answers and may also be a way to find a treatment that is more specific to your needs now or in the future, sometimes based on the specific type of mutation that is identified. Talk to your doctor to find out if genetic testing is an option for you.

PID and Neutropenia

People with neutropenia have a reduced number of neutrophils, a type of white blood cell. The lower the neutrophil count, the greater the risk of infection. Congenital neutropenia is both a rare blood disorder and a rare type of primary immunodeficiency (PID).

Neutropenia can also be described in three other ways:  as a “subclass” of PID, as a “feature of” or as “associated with” a specific PID (like WHIM syndrome). People living with neutropenia may see a specialist (like a hematologist or immunologist) to treat their neutropenia. Not all specialists describe neutropenia the same way and not all describe it as a type of PID. 

Types of Neutropenia

There are many ways to categorize neutropenia, which can make it even more confusing. Someone may be diagnosed with severe chronic neutropenia which can also be severe congenital neutropenia or benign neutropenia. You may be diagnosed with neutropenia but not know exactly what type you have. Or, you may not have been told about the neutropenia/PID link.

SeverityBased on ANC (Absolute Neutrophil Count) blood test:
Mild: ANC above 1000 per mm3
Moderate: ANC 500 per mm3 to 1000 per mm3
Severe: ANC < 500 per mm3 (0.5 x 109/l)
DurationAcute: temporary or short-lasting 
Chronic: long-lasting, neutropenia symptoms for more than 3 months
CyclicVarying neutrophil counts with a typical cycle length of 21 days
CauseCongenital: neutropenia that one is born with, runs in families or has a genetic cause
Acquired: neutropenia that is caused by something else over a period of time
Idiopathic: neutropenia whose cause is unknown

A genetic test may be able to help you learn more about your neutropenia and your treatment options. Keep in mind, there is no one perfect neutropenia panel/test. Each panel includes or leaves off certain genes. A mutation can be missed on whole exome sequencing and found on targeted mutation analysis; and vice versa.

Questions to Ask Your Doctor About Genetic Testing

  • Have I had a genetic test?
  • If I had genetic testing done before, should I have it done again since there are now tests that look at over 400 genes?
  • There are free genetic tests available with a doctor’s referral. Do I qualify for one?
  • Is there a chance my diagnosis might change depending on the results of a genetic test?
  • Would my treatment change if a genetic test finds that I have a specific type of PID?
  • Are there any clinical trials that I might qualify for based on the results of a genetic test?