The diagnosis of NF2 was initially based on the National Institutes of Health (NIH) criteria, which are as follows:
Bilateral masses of the eighth cranial nerve, seen with appropriate imaging techniques, plus
A first-degree relative with NF2 and
Subsequently, the more sensitive Manchester criteria were formulated as a modification of the NIH criteria. The Manchester criteria are more widely used. The main criteria are as follows:
Bilateral vestibular schwannomas or family history of NF2, plus
Unilateral vestibular schwannoma, or
Any two of the following:
Posterior subcapsular lenticular opacities
Additional criteria include the following:
Unilateral vestibular schwannoma, plus any two of the following:
Posterior subcapsular opacities, or
Multiple meningiomas (≥ 2) plus unilateral vestibular schwannoma or any two of the following:
The clinical diagnosis can be then confirmed by molecular genetic testing for the NF2 gene on chromosome 22. Neuroimaging aids in delineating cranial and spinal tumors. Audiometry and brain stem auditory evoked responses are also abnormal. Nerve conduction studies may reveal polyneuropathy in around 40% of cases. Nerve biopsy may demonstrate onion bulb formation.
Presymptomatic molecular genetic testing is a vital component of management of the families of patients with NF2. Individuals with a first-degree relative with NF2, those with multiple spinal tumors, and those with cutaneous schwannomas must be screened for NF2.[21,22] Prenatal diagnosis is also important. Prompt recognition of patients with NF2 is important to minimize subsequent complications.
Once the NF2 mutation is identified, these patients should receive routine follow-up. MRI of the brain and spine should be repeated every 2 years for individuals younger than 20 years and every 3-5 years after age 20 years. Yearly assessment of hearing should be performed, along with evaluation of eyes and skin. No further tests or follow-up is warranted in individuals who are negative for the affected gene.
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Cite this: Sumaira Nabi, Shahzad Ahmed, Mazhar Badshah. Bilateral Deafness and Skin Lesions in a 23-Year-Old Man - Medscape - Oct 12, 2016.