Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1

Neurofibromatosis Type 1 (NF1) is a tumor-predisposition syndrome caused by heterozygous mutations in the NF1 gene. In addition to oncologic manifestations, individuals with NF1 face a heightened risk of developing secondary skeletal complications associated with somatic loss-of-heterozygosity. Long...

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Main Authors: Aysha Khalid, PhD, Nandina Paria, PhD, Jonathan J. Rios, PhD
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:Journal of the Pediatric Orthopaedic Society of North America
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Online Access:http://www.sciencedirect.com/science/article/pii/S276827652500046X
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author Aysha Khalid, PhD
Nandina Paria, PhD
Jonathan J. Rios, PhD
author_facet Aysha Khalid, PhD
Nandina Paria, PhD
Jonathan J. Rios, PhD
author_sort Aysha Khalid, PhD
collection DOAJ
description Neurofibromatosis Type 1 (NF1) is a tumor-predisposition syndrome caused by heterozygous mutations in the NF1 gene. In addition to oncologic manifestations, individuals with NF1 face a heightened risk of developing secondary skeletal complications associated with somatic loss-of-heterozygosity. Long bone dysplasia and post-fracture pseudarthrosis are among the earliest skeletal manifestations observed in children with NF1. Most commonly occurring in the tibia, pseudarthroses are often treated with a combination of resection, fixation, bone grafting, and rhBMP2. Although rates of initial union are reported to be high, the risk of re-fracture and subsequent pseudarthrosis is similarly elevated, and some patients may ultimately require amputation. Basic science research related to NF1 pseudarthrosis is uncovering the cellular pathogenesis of the disease and unlocking new potential treatment paradigms. Here, we review the current understanding of the biological etiology of NF1 pseudarthrosis, informed by molecular studies of patient-derived tissue samples and mechanistic studies utilizing pre-clinical mouse models. Results from these studies are presented within the context of contemporary treatment paradigms. Finally, we introduce novel treatment paradigms currently under investigation in pre-clinical models and discuss how these may potentially translate to improve surgical outcomes in children with NF1 pseudarthrosis. Key Concepts: (1) Fracture pseudarthrosis in patients with NF1 is caused by somatic mutations in the NF1 gene. (2) Somatic NF1 gene mutations hyperactivate the MAPK signaling pathway, disrupting cellular mechanisms necessary for proper fracture healing. (3) Emerging therapies aim to target hyperactive MAPK signaling to promote fracture healing by fostering osteogenic instead of fibrogenic pathways in skeletal progenitor cells.
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spelling doaj-art-56ed1fb0805b458c8ffccada45e072552025-08-20T03:51:25ZengElsevierJournal of the Pediatric Orthopaedic Society of North America2768-27652025-08-011210020210.1016/j.jposna.2025.100202Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1Aysha Khalid, PhD0Nandina Paria, PhD1Jonathan J. Rios, PhD2Center for Translational Research, Scottish Rite for Children, Dallas, TX, USACenter for Translational Research, Scottish Rite for Children, Dallas, TX, USACenter for Translational Research, Scottish Rite for Children, Dallas, TX, USA; Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, TX, USA; McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, TX, USA; Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX, USA; Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas, TX, USA; Corresponding author: Scottish Rite for Children, 2222 Welborn St, Dallas, TX 75219, USA.Neurofibromatosis Type 1 (NF1) is a tumor-predisposition syndrome caused by heterozygous mutations in the NF1 gene. In addition to oncologic manifestations, individuals with NF1 face a heightened risk of developing secondary skeletal complications associated with somatic loss-of-heterozygosity. Long bone dysplasia and post-fracture pseudarthrosis are among the earliest skeletal manifestations observed in children with NF1. Most commonly occurring in the tibia, pseudarthroses are often treated with a combination of resection, fixation, bone grafting, and rhBMP2. Although rates of initial union are reported to be high, the risk of re-fracture and subsequent pseudarthrosis is similarly elevated, and some patients may ultimately require amputation. Basic science research related to NF1 pseudarthrosis is uncovering the cellular pathogenesis of the disease and unlocking new potential treatment paradigms. Here, we review the current understanding of the biological etiology of NF1 pseudarthrosis, informed by molecular studies of patient-derived tissue samples and mechanistic studies utilizing pre-clinical mouse models. Results from these studies are presented within the context of contemporary treatment paradigms. Finally, we introduce novel treatment paradigms currently under investigation in pre-clinical models and discuss how these may potentially translate to improve surgical outcomes in children with NF1 pseudarthrosis. Key Concepts: (1) Fracture pseudarthrosis in patients with NF1 is caused by somatic mutations in the NF1 gene. (2) Somatic NF1 gene mutations hyperactivate the MAPK signaling pathway, disrupting cellular mechanisms necessary for proper fracture healing. (3) Emerging therapies aim to target hyperactive MAPK signaling to promote fracture healing by fostering osteogenic instead of fibrogenic pathways in skeletal progenitor cells.http://www.sciencedirect.com/science/article/pii/S276827652500046XBasic-scienceNeurofibromatosisPseudarthrosisGenetics
spellingShingle Aysha Khalid, PhD
Nandina Paria, PhD
Jonathan J. Rios, PhD
Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
Journal of the Pediatric Orthopaedic Society of North America
Basic-science
Neurofibromatosis
Pseudarthrosis
Genetics
title Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
title_full Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
title_fullStr Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
title_full_unstemmed Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
title_short Molecular Basis of Fracture Pseudarthrosis Associated with Neurofibromatosis Type 1
title_sort molecular basis of fracture pseudarthrosis associated with neurofibromatosis type 1
topic Basic-science
Neurofibromatosis
Pseudarthrosis
Genetics
url http://www.sciencedirect.com/science/article/pii/S276827652500046X
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