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Background: Four sets of clinical diagnostic criteria for neurofibromatosis 2 (NF2) have been developed by groups of expert clinicians, but sensitivity has never been formally assessed. The sets of criteria differ for people without bilateral vestibular schwannomas, which are pathognomonic for NF2. Objective: To empirically evaluate the four existing sets of clinical diagnostic criteria for NF2. Methods: The study was based on 163 of 403 people in the United Kingdom NF2 registry (41%) who presented without bilateral vestibular schwannomas. The authors applied the sets of criteria to each person at initial assessment and at the most recent clinical evaluation (mean ± SE length of follow-up, 13 ± 1 years). Results: In people with “definite NF2” and a negative family history of NF2, the 1987 US NIH and 1991 NIH criteria each identify 78% of people at the most recent clinical evaluation but 0% at initial assessment. The National Neurofibromatosis Foundation (NNFF) criteria and the Manchester criteria each identify higher proportions at both time points (NNFF criteria, 91% and 10%; Manchester criteria, 93% and 14%), but the proportions at initial assessment are still low. Conclusions: None of the existing sets of criteria are adequate at initial assessment for diagnosing people who present without bilateral vestibular schwannomas as having NF2, particularly people with a negative family history of NF2. The authors recommend that a single, revised set of diagnostic criteria be devised to replace all of the existing sets of criteria.

Diagnostic criteria for schwannomatosis have been proposed in a recent consensus statement. These criteria permit schwannomatosis to be distinguished from neurofibromatosis type 2 (NF2) in most patients, but there is some clinical overlap between the two diseases. In this study, the authors use data from the population-based United Kingdom NF2 Registry to recommend modifications that increase the specificity of the schwannomatosis diagnostic criteria.

Mutations of the neurofibromatosis 2 (NF2) tumor suppressor gene cause the inherited disorder NF2 and are also common in malignant mesothelioma, which is not a characteristic feature of NF2. The authors report an asbestos-exposed person with NF2 and malignant mesothelioma. Immunohistochemical analysis of the mesothelioma confirmed loss of expression of the NF2 protein, and comparative genomic hybridization revealed losses of chromosomes 14, 15, and 22, and gain of 7. The authors propose that a person with a constitutional mutation of an NF2 allele is more susceptible to mesothelioma.

Neurofibromatosis 2 (NF2) is an autosomal dominant disorder that causes nervous system tumors and ocular abnormalities such as early-onset lenticular opacities. We assessed the clinical spectrum of NF2 at the time of presymptomatic DNA diagnosis in at-risk first-degree relatives. We studied five multigeneration NF2 families with short tandem repeat markers near the NF2 gene (NF2); gadolinium-enhanced high-resolution magnetic resonance imaging (GE-MRI); and ocular, dermatologic, and neurologic examinations. Eleven of 31 asymptomatic at-risk first-degree relatives were predicted by segregation analysis to be NF2 mutation carriers. Nine of the 11 NF2 mutation carriers were clinically evaluated. Four mutation carriers, including a 7-year-old, had vestibular schwannomas, early-onset cataracts, or both. However, five mutation carriers did not have clinical abnormalities, including a 38-year-old with normal cranial and spinal GE-MRIs and a normal ocular examination. These results indicate that clinical abnormalities can be present in young, but absent in middle-aged, presymptomatic NF2 mutation carriers. By identifying presymptomatic NF2 mutation carriers, DNA diagnosis of NF2 can improve genetic counseling and clinical management, and possibly reduce psychosocial difficulties in at-risk individuals.NEUROLOGY 1996;47: 1269-1277

We identified a missense mutation (T185 right arrow C, Phe62 right arrow Ser) in the neurofibromatosis 2 (NF2) gene in a family with mild and severe NF2 phenotypes.This mutation was previously reported in an unrelated family in which all affected individuals had mild phenotypes. These data demonstrate a lack of correlation between NF2 genotype and NF2 phenotype for this mutation.NEUROLOGY 1996;47: 544-546