SCID is a rare disease that appears in infancy. It causes affected children to have a very weak immune system. There are now tests and treatments for this severe, inherited condition.
Severe combined immunodeficiency disease (SCID) is a very rare genetic disorder that affects about 1 in every 100,000 births in the United States. This condition causes an incredibly weak immune system.
Until very recently, SCID was nearly always fatal. Children with SCID typically died in early childhood after repeated and frequent infections. It was common for SCID to be undiagnosed until a child was about 6 months old and already seriously ill.
Today, thanks to newborn screening, early interventions, and advances in treatments, children with SCID can be successfully treated.
Options such as bone marrow transplants can repair a child’s immune system, and treatments such as immunoglobulin and enzyme replacement therapy help keep children healthy while they wait for bone marrow transplants.
Children who are treated in the first few months of life have high odds of a good treatment outcome.
There are a few different types of SCID caused by different inherited abnormalities. Knowing the exact type can help doctors determine the best treatment plan. However, all types of SCID share a weak immune system as their primary symptom.
Types of SCID include:
- classical X-linked SCID
- ADA deficiency SCID
- leaky SCID
- variant SCID
What is ‘boy in the bubble’ syndrome?
SCID is sometimes called “boy in the bubble” syndrome, due to a highly publicized case in the 1970s of a boy named David Vetter who had SCID and lived his life in a sterile plastic chamber.
Treatment of SCID has improved significantly since then. Children today have much better options and a much better outlook.
SCID is genetic. Several genetic abnormalities can lead to SCID. The condition can be inherited as either an autosomal recessive trait or as an X-linked trait:
- Recessive genetic traits: These traits are passed on when each parent carries the trait and the child inherits two copies of the trait. Generally, someone with one copy of the genetic trait for a disorder or condition will be a carrier but won’t have that condition. Two carrier parents have a 25% chance of having a child with the condition.
- X-linked conditions: These conditions are passed down on the X chromosome and occur more often in men. This is because women normally only have the trait on one X chromosome, making them unaffected carriers.
There are no known environmental risk factors for SCID.
The most common symptom of SCID is frequent respiratory infections. Often, these respiratory infections are severe enough that hospital treatment is needed. Additional symptoms include:
Today, SCID is primarily detected through newborn screenings. This is often done as part of the same screening as the heel prick blood test that screens for:
Depending on the results of the screening, further blood tests might be done. These tests can look at immune system function and genetic markers of SCID.
Additionally, if you know you have a family history of SCID, there are in-utero tests that can be done.
Early treatment is very important for children with SCID. The exact treatment plan will depend on your child’s exact needs. Common treatments include:
- Antibiotics: Antibiotics treat and prevent infections.
- Immunoglobulin replacement: Immunoglobulin replacement is a short-term therapy that uses donated plasma to provide antibodies to a child with SCID.
- Enzyme replacement therapy: Enzyme replacement therapy repairs defective proteins in the body so that the immune system can gain function.
- Bone marrow transplant: At this time, a bone marrow transplant is the only cure for SCID. Bone marrow transplants have the highest success rates when they’re performed in the first 3 months of a child’s life and when the donor is a healthy relative.
Gene therapy for severe combined immunodeficiency
Gene therapy is an emerging option for SCID. It could be a breakthrough for children who are unable to receive a bone marrow transplant or for whom bone marrow transplants don’t work. Gene therapy has been shown to successfully restore immune cell function in children.
However, this treatment is still experimental. In the United States, it’s only available through clinical trials. Gene therapy is currently available in Europe, and clinical trials are being conducted by the United States National Institute of Health and multiple children’s hospitals.
If you want to get involved in a clinical trial, you can check out what’s available at ClinicalTrials.gov. Always make sure to discuss any trial with your child’s doctor before signing up, especially if it would involve any change to their treatment plan.
Can severe combined immunodeficiency be cured?
SCID can be cured with early treatment. Children who are treated in the first 3 months of life and who receive a bone marrow transplant from a donor-matched sibling have the best odds of a successful treatment outcome.
Treatment of SCID has changed dramatically in recent decades. In the past, children with SCID had a very short life expectancy.
Today, early screening and early treatment are changing that. Life expectancy now depends on when the diagnosis is made, when treatment is received, and on the response to treatment. With a bone marrow transplant, many children with SCID are successfully treated and cured.
Living with SCID in the family
SCID can be a frightening and overwhelming diagnosis to hear for your child. It’s important to reach out for support. There are some great resources to help. You can check out:
- The Immunodeficiency Foundation (IDF): IDF has support groups for parents, local meetups, online resources, video meetups, and more.
- SCID Compass Caregiver Support Group: The Educational foundation SCID Compass offers this virtual support group for parents and other caregivers of children with SCID.
- SCID Angels For Life Foundation: The SCID Angels For Life Foundation is a charitable organization that aims to provide financial assistance and support to families of children with SCID. You’ll also find educational resources, online support groups, news about clinical trials, and more.
- The SCID Email Listserv Support Group: The SCID group offers this listserv support group for parents, caregivers, and others with close connections to SCID.
SCID is a rare inherited disorder that causes a weakened immune system. Children with this condition have weak immune systems that can’t fight infections. Without treatment, SCID is fatal, and in the past, most children with this condition had a very short life expectancy.
Today, early screening and improved treatments have improved the outlook for children with SCID. In many cases, it can be fully cured.
Bone marrow transplants can completely cure SCID, and treatment is especially successful when it’s done during the first 3 months of a child’s life. In the near future, gene therapy might provide an answer for children who are unable to receive bone marrow transplants.