Specialized Care and Treatment Strategies for NBS

Managing Nijmegen Breakage Syndrome (NBS) requires a highly specialized medical approach. Because your child’s cells are missing the “repair crew” needed to fix DNA breaks, standard medical treatments—especially those for cancer and immune issues—must be carefully modified. The goal of care is to protect the immune system while avoiding treatments that could cause more harm than good ^[1][2].

Supporting the Immune System

Most children with NBS have some degree of immunodeficiency, meaning their body doesn’t produce enough antibodies to fight off germs ^[3]. To manage this, doctors often use two main strategies:

• Immunoglobulin Replacement Therapy: If your child has low antibody levels (IgG) or frequent infections, they may receive regular infusions of immunoglobulins (IVIG or SCIG) ^[3][4]. This “borrows” antibodies from healthy donors to help your child fight infections. Studies show this can significantly reduce the frequency and severity of respiratory illnesses ^[3].
• Antibiotic Prophylaxis: In some cases, especially during intensive treatments, doctors may prescribe a daily low-dose antibiotic or antifungal medicine to prevent infections before they start ^[1].

A Note on Vaccines: You should discuss all immunizations with your child’s immunologist. Live vaccines depend on a specialist’s assessment of your child’s T-cell function and are often avoided because they can be harmful ^[5].

Modifying Cancer Treatment

If a child with NBS develops a malignancy like lymphoma, the treatment plan must be radically different from a standard protocol.

1. Omitting Radiation: Standard radiotherapy (radiation) is generally avoided. Because NBS cells cannot repair the damage radiation causes, it can lead to life-threatening complications or new cancers ^[1][6].
2. Customizing Chemotherapy: Standard “full-dose” chemotherapy can be extremely toxic for a child with NBS. Pediatric oncologists individualize the regimen, selecting specific drugs and modifying dosages according to the malignancy, genotype, and expert protocol ^[1].
3. Increased Monitoring: Because the risk of complications like severe mouth sores (mucositis), lung issues, and organ toxicity is much higher, children with NBS require intensified supportive care and close monitoring during any treatment ^[1][2].

The Role of Stem Cell Transplant (HSCT)

A Hematopoietic Stem Cell Transplant (HSCT), also known as a bone marrow transplant, is a complex procedure that can replace the immune system. In NBS, it is not a routine preventive treatment; it does not correct the NBN defect in other tissues (like the brain or other organs), but it may be indicated for specific severe immune or marrow failure, or certain types of cancer ^[7][8].

• Reduced-Intensity Conditioning (RIC): A preferred approach for NBS transplants. Standard transplants use high doses of chemotherapy or radiation (myeloablative conditioning) to clear out the old marrow, which is too dangerous for children with NBS ^[9]. RIC uses lower, less toxic doses of chemotherapy to prepare the body for the new cells ^[9][10].
• The Benefits and Risks: While HSCT replaces the immune and blood system, it remains a high-risk procedure that can lead to serious complications like Graft-versus-Host Disease (GVHD) or severe infections ^[9][11].

Because these decisions are so complex, it is essential that your child is cared for at a center with specific expertise in treating DNA double-strand-break repair disorders ^[1][12].