Pathogenic variants (disease-causing) in the NF1 gene cause neurofibromatosis type 1, a multisystem condition marked by multiple benign tumors called neurofibromas, pigmented skin findings (café-au-lait spots), bone differences, and learning or behavioral challenges. Additionally, people with a pathogenic variant in NF1 also have an increased lifetime risk of several cancers including breast cancer, malignant peripheral nerve sheath tumors, and pheochromocytomas. Because NF1 is a lifelong, syndromic condition, care typically involves multidisciplinary teams that monitor growth, neurological status, hormone effects, and tumor development. NF1 variants are not known to be more common in the Ashkenazi Jewish population.
Pathogenic variants in NF1 exhibit autosomal dominant inheritance. This means there is a 50% chance the condition can be passed from generation-to-generation. First degree relatives (parents, siblings, children) have a 50% chance to have the same pathogenic variant whereas second degree relatives (grandparents, aunts/uncles, nieces/nephews, half-siblings) have a 25% chance. More distant relatives have lower chances of having the same pathogenic variant when one is identified in the family.
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Written December 2025
