Neurofibromatosis type II

Neurofibromatosis type II, usually called NF2, is an inherited disorder in which benign tumors develop on nerves in the brain, spinal cord and peripheral nervous system, and its defining feature is the growth of tumors on the nerve that controls hearing and balance on both sides of the head, called bilateral vestibular schwannomas. It results from mutations in the NF2 gene on chromosome 22, inherited in an autosomal dominant pattern, though about half of cases arise from a brand-new mutation rather than being passed down from a parent; the healthy version of this gene normally produces a protein called Merlin that helps suppress tumor growth, so its loss allows nerve-sheath tumors to form. Common symptoms include progressive hearing loss, ringing in the ears, balance problems, vision impairment, seizures and numbness in the arms or legs, typically emerging in adolescence or early adulthood and worsening as tumors enlarge. Diagnosis is usually made in the twenties, most often through MRI imaging that identifies the characteristic bilateral tumors on the hearing and balance nerve, supported by genetic testing to confirm an NF2 mutation. Treatment options include surgical removal of tumors, targeted radiosurgery, and medications such as bevacizumab that can shrink some tumors, alongside hearing rehabilitation measures including cochlear implants or auditory brainstem implants for patients who lose functional hearing.