What is Severe Congenital Neutropenia?

What happens when the body’s infection-fighting cells are too low from birth? For those living with severe congenital neutropenia (SCN), this rare condition—affecting about 1 in 200,000 people—can make everyday infections harder for your body to fight.

SCN happens when the bone marrow doesn’t produce enough neutrophils, a type of white blood cell that protects the body from bacteria and fungi.

Children with SCN often start showing signs early in life, such as frequent mouth sores, skin infections, or pneumonia. Because their immune systems are weaker, even a small cut or a mild cold can turn into something serious without proper treatment. The encouraging news is that with today’s medical care, children and adults with SCN can lead healthy, active lives. Regular checkups, preventive care, and the current SCN treatments can greatly help manage symptoms and reduce complications.

Severe Congenital Neutropenia 101

SCN refers to a group of rare blood disorders where the bone marrow doesn’t make enough neutrophils—a type of white blood cell that’s essential for fighting infections. Neutrophils usually make up about half to two-thirds of your immune cells and act as your body’s first line of defense against bacteria and fungi.

In severe congenital neutropenia patients, the number of neutrophils in the blood stays much lower than normal—typically below 500 cells per microliter, compared to healthy levels of 1,500–8,000. With so few of these protective cells, the body becomes more vulnerable to serious infections that most immune systems could easily handle.

In most cases, SCN happens because the bone marrow’s “neutrophil production line” gets stuck partway through. The marrow begins making these cells, but the process stops too early, leaving immature neutrophils that can’t do their job.

Think of it like an assembly line that suddenly stalls—the materials are there, but the finished products never make it out. This interruption leaves the immune system without enough fully developed neutrophils to keep infections at bay.

At California Specialty Pharmacy (CSP), an Acelpa Health company, we work closely with patients and their care teams to provide guidance, support, and access to the therapies that help manage SCN effectively, keeping the immune system as strong as possible.

Common Symptoms and Diagnosis

Recognizing the signs of severe congenital neutropenia early can make a big difference in starting the right treatment and preventing serious infections. Symptoms usually appear in the first few months of life—sometimes even at birth. Parents often notice that their baby seems to get sick more frequently than expected, or that infections are unusually severe and take longer to heal.

Common Symptoms

Some of the most common signs of SCN include:

Recurrent fevers without a clear cause, often signaling the body’s struggle to fight infection
Painful mouth ulcers, gum inflammation, or tooth abscesses that don’t heal properly
Skin infections such as boils, abscesses, or areas of redness and swelling (cellulitis) that spread quickly without treatment
Respiratory infections that can start as a mild cold but progress rapidly to pneumonia or other serious lung infections
Persistent diarrhea from intestinal infections that irritate or damage the gut lining

Getting a Diagnosis

Diagnosis typically begins when a child experiences repeated or unusually severe infections. Doctors may use several tests to confirm SCN, including:

Complete blood count (CBC): Measures the number of white blood cells, red blood cells, and platelets. An absolute neutrophil count (ANC) below 500 cells per microliter raises concern.
Bone marrow aspiration: Helps doctors see if neutrophil production has stopped partway through development.
Genetic testing: Identifies changes in specific genes—such as ELANE, HAX1, or G6PC3—that are known to cause SCN.

While the testing process can feel overwhelming, getting a clear diagnosis is an important step. It helps your child’s care team create a treatment plan tailored to their needs—empowering families to move forward with knowledge, support, and hope.

Causes and Genetic Factors

Understanding what causes SCN can help families make sense of why their child faces these challenges. At its core, SCN is usually the result of genetic mutations that disrupt the bone marrow’s ability to produce neutrophils, leaving the immune system with fewer “soldiers” to fight infections.

Genetic Mutations

Researchers have identified mutations in more than 24 different genes that can lead to SCN. Some of the most important include:

ELANE: Responsible for about 60% of cases, this gene provides instructions for making neutrophil elastase, a protein critical for neutrophil development. Mutations here create faulty neutrophil elastase, which causes developing neutrophils to die prematurely.
HAX1: Linked to the autosomal recessive form originally described as Kostmann disease.
G6PC3: Associated with SCN and additional features like heart defects or prominent blood vessels.
G-CSF receptor mutations: Affect how neutrophils respond to growth signals, which can interfere with their production.

Inheritance Patterns

SCN can be passed down in different ways, depending on the gene involved:

Autosomal dominant (ELANE): A child has a 50% chance of inheriting the condition if one parent carries the mutation. Many cases, however, come from new mutations, which means children can be affected even if both parents are healthy.
Autosomal recessive (HAX1 and some others): A child must inherit two copies of the mutated gene—one from each parent—to have the condition. Parents carrying only one copy are usually healthy, but each pregnancy carries a 25% chance of having a child with SCN.

Knowing the genetic basis of SCN can help families make informed decisions about care, treatment, and family planning—providing clarity and reassurance during a challenging time.

Treatment Approaches

Managing severe congenital neutropenia usually involves a comprehensive plan that combines medications, preventive care, and occasionally more intensive interventions. Every treatment plan is personalized, taking into account genetic findings, infection history, and how a patient responds to medications.

G-CSF Therapy

Granulocyte colony-stimulating factor (G-CSF) is the cornerstone of SCN treatment. It helps the bone marrow produce more neutrophils, boosting the body’s ability to fight infections.

Most patients start with daily injections of medications such as Neupogen (filgrastim) or biosimilar options like Zarxio, Nivestym, and Releuko.
Long-acting pegylated versions like Neulasta, Udenyca, Fulphila, and Ziextenzo allow for weekly dosing in some patients.

At California Specialty Pharmacy (CSP), we help coordinate insurance benefits, teach injection techniques, and provide 24/7 support for any questions about dosing or side effects.

Advanced Treatment Options

In some cases, G-CSF therapy may not be enough, or patients may develop complications such as acute myelogenous leukemia (AML). For these patients, hematopoietic stem cell transplantation can replace malfunctioning bone marrow with healthy donor cells, potentially curing the underlying neutropenia.

Some patients also benefit from IVIG therapy (intravenous immunoglobulin) with products like Gamunex-C, Gammagard Liquid, Privigen, or Octagam, offered by CSP, when infections persist despite G-CSF treatment. Home infusion can help make these complex treatments more manageable in daily life.

With the right combination of therapies, regular monitoring, and support from a knowledgeable care team, patients with SCN can stay healthier, reduce infection risks, and live active, fulfilling lives.

Long-Term Outlook

Thanks to advances in care, the long-term outlook for people with SCN is far brighter than it once was. With consistent treatment, regular monitoring, and a supportive care team, many patients live full, active lives—pursuing careers, raising families, and enjoying the milestones that once seemed out of reach.

Studies show that patients who respond well to G-CSF therapy and experience fewer complications can now have a much higher life expectancy—a hopeful sign of how far treatment has come.

Managing Complications

Even with better treatments today, people with SCN still face some risks that require careful monitoring:

Myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML): These serious conditions develop in about 10–20% of patients over their lifetime.
Mutation or changes in blood cells: Regular blood tests help detect early warning signs, such as new G-CSF receptor mutations or changes in how blood cells look and behave.
Infection risk: Even with treatment, patients may still experience breakthrough infections, especially during illness, stress, or after medical procedures.

At California Specialty Pharmacy, we understand that managing SCN is a lifelong journey. Our pharmacists and care coordinators provide a personalized care plan and continuous support—helping with medication adjustments, insurance coordination, and guidance to make every stage of care as seamless as possible.

Quality of Life

With proper precautions and care, children and adults with SCN can lead active, fulfilling lives:

Children can attend school, join activities, and play sports with guidance from their care team.
Adults often work in a wide range of professions, sometimes avoiding environments with high infection risks.
Pregnancy is possible for many women with SCN, though it requires careful planning and coordination between hematology and obstetrics specialists.
Support groups play an invaluable role—connecting families who share similar experiences, offering emotional encouragement, and sharing practical advice for everyday living.

Living with SCN may come with challenges, but with the right medical care, ongoing support, and proactive monitoring, patients can look forward to long, meaningful lives filled with hope and possibility.

Living Well with Severe Congenital Neutropenia

Living with severe congenital neutropenia means navigating unique challenges—but it also means having access to treatments, support, and resources that can make a lasting difference. Today, most patients can lead long, active lives thanks to modern therapies, preventive care, and close collaboration between specialists, pharmacists, and families. With regular monitoring and a strong partnership with your healthcare team, it’s possible to manage symptoms, reduce infection risks, and live life with greater confidence and peace of mind.

At California Specialty Pharmacy (CSP), we know that managing a rare condition like SCN takes more than just medication—it takes compassion, guidance, and dependable support. Our experienced team helps patients and caregivers every step of the way, from navigating insurance approvals to providing 24/7 clinical support and personalized education.

If you or your loved one is living with SCN, CSP is here to help. We’ll work closely with your care team to simplify treatment, ensure access to the right medications, and empower you to live fully and well. Learn more or contact us today to see how CSP can support your SCN care journey.

Frequently Asked Questions

What is severe congenital neutropenia, and how does it affect patients?

Severe congenital neutropenia is a rare genetic blood disorder that causes very low proper functioning neutrophil levels, the white blood cells that fight infections. People with SCN are prone to recurrent bacterial infections, which can be serious without treatment. It’s caused by gene mutations that affect neutrophil production in the bone marrow.

What treatments are available for severe congenital neutropenia?

The main treatment is daily G-CSF injections to boost neutrophil production. Some patients may also need preventive antibiotics or antifungal medications. In rare cases, if G-CSF isn’t enough or blood cancers develop, bone marrow transplantation may be needed.

How is severe congenital neutropenia diagnosed?

SCN is usually suspected in infants with recurrent severe infections. To confirm the diagnosis, there are blood tests that will show low neutrophil counts, and a bone marrow exam can reveal stalled neutrophil development. Genetic testing confirms the diagnosis and helps explain inheritance patterns.

What is the long-term outlook for patients with severe congenital neutropenia?

With consistent G-CSF therapy, most patients can manage and have active, fulfilling lives with fewer infections. Lifelong monitoring is important, as 10–20% may develop blood cancers. Regular blood tests help track treatment response and detect early warning signs.

References:

Cleveland Clinic, 2025. Neutrophils.
https://my.clevelandclinic.org/health/body/22313-neutrophils
Cincinnati Children’s Hospital Medical Center, 2025. Severe congenital neutropenia.
https://www.cincinnatichildrens.org/health/s/severe-congenital-neutropenia
MedlinePlus, 2025. Severe congenital neutropenia.
https://medlineplus.gov/genetics/condition/severe-congenital-neutropenia/
Sukumar, S., et al., 2018. Severe congenital neutropenia: pathophysiology, clinical features, and management. PMC.
http://pmc.ncbi.nlm.nih.gov/articles/PMC5821468/

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