Letter to Jmg

N eurofibromatosis 2 (NF2) is an autosomal dominant disease associated with mutations in the gene NF2. In clinical practice, the diagnosis is made if a patient satisfies the 1987 National Institutes of Health diagnostic criteria, which are either the presence of bilateral vestibular schwannomas or a first degree relative with NF2 and a unilateral vestibular schwannoma, or any two of the following: meningioma, schwannoma, glioma, neurofibroma, or juvenile posterior subcapsular lenticular opacity. These strict criteria have since been slightly relaxed to incorporate more patients who do not quite fulfil the diagnostic criteria but are thought nevertheless to have NF2. 4 We report here a patient who was found to have NF2, by the strict criteria, and who had severe intellectual disability. Further investigation revealed a de novo balanced reciprocal translocation. We have fine mapped the chromosome 22 breakpoint and its relation to NF2 and established the effect of this translocation in various tissues from the patient.