The Children's Tumor Foundation
04/22/2026 | Press release | Distributed by Public on 04/22/2026 08:08
2026 NF Knowledge Series: Segmental and Mosaic NF
The April NF Knowledge Series focused on Segmental and Mosaic NF was hosted by Alicia Gomes, MS, CGC, University of Alabama at Birmingham. The webinar allowed participants to better understand mosaic and segmental forms of NF and what they mean for individuals and their families.
What is Mosaic NF?
In most individuals with NF, the change in the gene that leads to the condition occurs at or before fertilization. The gene variant might be inherited from one of the parents, or it may be a new genetic change that occurred in the formation of the egg or sperm cell. As the cells divide and duplicate, all cells of the developing embryo have the genetic variant, leading to the classic (non-mosaic) form of NF.
In some situations, however, the change in the gene occurs after fertilization. Neither the egg nor the sperm cell from either parent has the genetic variant, but as the cells divide, a genetic change can happen. Because the genetic change occurs later in embryonic development, after some cell divisions have already occurred, there is a mixture of cells; some with the normal gene and some with the variant gene. This combination, in which only some cells have the genetic variant, is referred to as mosaicism. Individuals with mosaicism are always the first person in their family to have the condition. We do not know what causes these genetic changes to occur, but it is not something the mother or father did or did not do before or during a pregnancy.
What is Segmental NF?
Segmental NF is a specific type of mosaicism that also results from a mixture of cells with normal and variant genes. However, in segmental NF, the cells with the variant gene are localized to only one region or segment of the body, while the other areas have only normal cells. The areas with the variant genes may be visible on the outside of the body; however, it can sometimes be difficult to predict which cells or how many cells within the body are affected.
Take Action
By understanding the nuances of mosaicism, we can better support individuals and families affected by NF, empowering them with knowledge and resources to manage their condition effectively.
Download the new educational resource on mosaicism and segmental NF from the Children's Tumor Foundation, in English and Spanish.
Register for the upcoming NF Summit to connect with experts and the NF community.
View more information about our upcoming NF Knowledge Series webinars.
Watch a recording of the webinar below.
The Children's Tumor Foundation published this content on April 22, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on April 22, 2026 at 14:08 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]