Emerging approaches toward the treatment of neurofibromatoses

Genetically engineered minipigs model the major clinical features of human neurofibromatosis type 1

Neurofibromatosis Type 1 (NF1) is a genetic disease caused by mutations in Neurofibromin 1 (NF1). NF1 patients present with a variety of clinical manifestations and are predisposed to cancer development. Many NF1 animal models have been developed, yet none display the spectrum of disease seen in patients and the translational impact of these models has been limited. We describe a minipig model that exhibits clinical hallmarks of NF1, including café au lait macules, neurofibromas, and optic pathway glioma. Spontaneous loss of heterozygosity is observed in this model, a phenomenon also described in NF1 patients. Oral administration of a mitogen-activated protein kinase/extracellular signal-regulated kinase inhibitor suppresses Ras signaling. To our knowledge, this model provides an unprecedented opportunity to study the complex biology and natural history of NF1 and could prove indispensable for development of imaging methods, biomarkers, and evaluation of safety and efficacy of NF1-targeted therapies.

The phakomatoses

The phakomatoses are a diverse set of disorders related principally by a similar tendency to produce patchy manifestations that affect the nervous system and various other tissues. All of the disorders involve the occurrence of benign neoplasms or hamartomatous growths, and all involve the action of a distinct gene that functions as a tumor suppressor. At present, none of the phakomatoses is amenable to effective medical treatment, so management is limited to surveillance and treatment of progressive lesions. The radiologist plays a key role in this management, participating in diagnosis and follow-up of affected patients.

Neuroimaging findings in neurofibromatosis type 1 and 2

Neuroimaging, particularly MR imaging, plays an important role in the diagnosis and management of the patient with neurofibromatosis type 1 and 2. These phakomatoses are complex disorders affecting multiple cell types and multiple systems of the body with a wide range of expression. This article summarizes the neuroradiologic central nervous system findings in these neurocutaneous disorders.

Interobserver reproducibility of volumetric MR imaging measurements of plexiform neurofibromas

OBJECTIVE

This article validates the reproducibility of MR imaging volumetric measurements for evaluating the growth of plexiform neurofibromas in neurofibromatosis type 1.

CONCLUSION

Volumetric measurements of plexiform neurofibromas in neurofibromatosis 1 are reproducible.

Neurofibromas in children with neurofibromatosis 1

Neurofibromatosis 1 is a common autosomal dominant disease reported in approximately 1 in 3000 individuals. Although some features of neurofibromatosis 1, such as café-au-lait spots and Lisch nodules, are clinically silent, neurofibromas cause a significant degree of morbidity, mortality, and cosmetic disfigurement. Childhood through early adulthood is a vulnerable period for the growth of these lesions. Neurofibromas are a heterogeneous group of benign tumors that grow from intraneural and extraneural tissues. These tumors take on different morphology, grow at variable rates, and occur in multiple locations. Symptoms arise as neurofibromas enlarge, compressing and distorting local structures. The unpredictable nature of neurofibromas has a serious impact on the quality of life of patients with neurofibromatosis 1, and their management is challenging for physicians. Surgical removal remains the mainstay of treatment. However, advances in the understanding of the genetics and pathogenesis of neurofibromatosis 1 have led to the development of promising new biologically directed therapies. The purpose of this review is to summarize the defining characteristics, incidence, clinical course, management options, and outcome of neurofibromas in children with neurofibromatosis 1.