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Neurofibromatosis Types 1 and 2
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Neurofibromatosis type 2 (NF2, sometimes referred to as central neurofibromatosis) is an autosomal dominant disorder that predisposes to the development of benign (noncancerous) tumors (typically vestibular schwannomas or acoustic neuromas, meningiomas of the brain, and schwannomas of the dorsal roots of the spinal cord, but few skin lesions or neurofibromas) in the nervous system, leading to hearing loss, ringing in the ears (tinnitus), changes in vision (including clouding of the lens or cataracts), numbness or weakness in the arms or legs, and fluid buildup in the brain. NF2 has an estimated incidence of 1 in 25,000–33,000. Mutations in the NF2 gene on chromosome 22q12.2 encoding merlin (NF2), which functions as a tumor suppressor, appear to be responsible for NF2 [3].
Rare Mendelian cancer syndromes and other cancers
Published in Angus Clarke, Alex Murray, Julian Sampson, Harper's Practical Genetic Counselling, 2019
Neurofibromatosis type 2 (NF2) is an autosomal dominant condition caused by mutations in the NF2 gene. It affects about 1 in 35,000 people, making it much less common than NF1 (see Chapter 14). The hallmark features of NF2 are bilateral vestibular schwannomas, which are benign tumours growing on the vestibular nerves. Other tumours found in NF2 include meningiomas of the brain and spinal cord, spinal schwannomas and cutaneous schwannomas. The vestibular schwannomas almost inevitably cause hearing loss of some degree, and this is commonly one of the first signs of the condition.
Cochlear Implants
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Andrew Marshall, Stephen Broomfield
Hearing loss in patients with neurofibromatosis type 2 (NF2) may be secondary to bilateral vestibular schwannomas or their treatment. Using modern surgical techniques, it is sometimes possible to excise tumours with preservation of the cochlear nerve. This allows for consideration of CI rather than auditory brainstem implantation, with more reliable outcomes. Intra-operative testing using electrically evoked auditory brainstem responses or cochlear nerve action potentials may be used to determine whether a cochlear implant is appropriate. In England, the four specialist NF2 centres have agreed a protocol for the management of hearing loss in this challenging group.17
Interplay between EGFR, E-cadherin, and PTP1B in epidermal homeostasis
Published in Tissue Barriers, 2023
Tessa Arnaud, Fernando Rodrigues-Lima, Mireille Viguier, Frédérique Deshayes
Beyond the catenins, other partners of the AJ complex have been shown to be crucial in the interaction between EGFR and E-cadherin. PLEKHA7, a recently demonstrated new component of the AJ, is known to stabilize the molecular complex of E-cadherin by linking it to the minus ends of non-centrosomal microtubules.29 However, it also appears that this molecule obliterates the interaction between EGFR and E-cadherin since upon PLEKHA7 overexpression in epithelial ovarian cancer, the association of E-cadherin with EGFR is lost and subsequent EGFR activation inhibited.37,44 This type of interaction has also been illustrated for the neurofibromatosis type-2 (NF2) tumor suppressor and Merlin (also known as schwannomin). Merlin has been described to be recruited at the cadherin/catenin complex and to regulate cell adhesion.45,46 A few years later it has been demonstrated that it could also binds to and regulates EGFR trafficking through NHE-FR147 and hence by this interaction with both E-cadherin and EGFR coordinate membrane receptor signaling and adhesion in mammalian cells.48
Hearing preservation/rehabilitation surgery for small vestibular schwannoma: preliminary experience with the presigmoid retrolabyrinthine approach
Published in Acta Oto-Laryngologica, 2021
Jie Wang, Yong Li, Xingmei Wei, Jingyuan Chen, Lifang Zhang, Xinping Hao, Yongxin Li
The patients’ demographics, tumor sizes, surgical methods, pre- and postoperative hearing classes, postoperative facial nerve function, and follow-up times are shown in Table 2. Five patients were women, and five were men. The median age was 55 years (range, 30–67 years). Six tumors were on the left side, three were on the right. One patient had neurofibromatosis type 2 (NF2) with bilateral involvement. Surgery was performed on the right side. The patients had various degrees of preoperative hearing loss. Eight patients presented with tinnitus and one presented with headache. No facial paralysis was present before surgery. On preoperative hearing tests, one patient was class A, four were class B, four were class C, and one was class D (NF2) according to the AAO-HNS hearing classification system for VS. The median tumor size was 11.7 × 4.85 mm (range, 5 × 3 mm to 15 × 10 mm). According to the Koos classification, three patients were grade I, six were grade II, and the patient with NF2 was grade III.
Development of a multidisciplinary clinic of neurofibromatosis type 1 and other neurocutaneous disorders in Greece. A 3-year experience
Published in Postgraduate Medicine, 2019
Eleftheria Kokkinou, Kleoniki Roka, Alexis Alexopoulos, Efthymia Tsina, Ioannis Nikas, Panagiotis Krallis, Ioanna Thanopoulou, Lambrini Nasi, Evanthia Makrygianni, Eirini Tsoutsou, Konstantina Kosma, Maria Tsipi, Maria Tzetis, Helen Frysira, Antonis Kattamis, Roser Pons
NF1, formerly known as von Recklinghausen disease (OMIM 162,200) is the most common type of NCS with an incidence of 1 in 2600 to 3000 individuals. NF1 belongs to the group of neurofibromatoses that is an umbrella term for three genetically distinct disorders: NF1, neurofibromatosis type 2 (NF2) and schwannomatosis. They all have a common tendency toward the development of tumors of the nerve sheath, but the specific manifestations are distinct [9–11]. NF1 results from mutations in the NF1 gene that encodes the tumor suppressor protein neurofibromin. Approximately half of the cases are inherited in an autosomal dominant manner, and the other half are the result of de novo mutations. Cafe-au-lait macules are the pathognomonic cutaneous manifestations of NF1 that are often present at birth and/or gradually appear in the first postnatal months. The clinical diagnosis can be confirmed by the diagnostic criteria of NF1 developed by the United States National Institutes of Health Consensus Conference in 1987 and updated in 1997 (Table 1) [11–13]. Genetic testing is often not required for the diagnosis but can be helpful in confirming it for children who do not meet diagnostic criteria or only demonstrate cafe-au-lait macules and axillary freckling [10].