We're not giving up
Lewis' condition is neurofibromatosis type II. It is a genetic disorder that causes benign tumours in the brain and/or throughout the central nervous system, often accompanied by peripheral tumours. It only affects 1 in 40,000 people, usually in the late teens or early twenties, and this is the reason why Lewis is such a special little boy - nobody ever expected the condition to develop in one so young.
The tumours caused by NF2 are called either neurofibromas or schwannomas, and grow on nerves, causing pressure and eventually damage just by being there. Symptoms vary depending on which nerves are involved, and the size of the tumours. In Lewis' case, the tumours are wrapped around the carotid artery, which is the main source of blood to the brain, and the cranial nerve, which is why his eye is affected.
NF2 is caused by a defect in a gene on chromosome 22. The affected gene has been identified, but there is currently no cure.
Since the onset of NF2 usually occurs in the late teens or early twenties, scanning usually starts at this age. The most important tests for detecting the condition are brain imaging and hearing tests; other important tests are neurological examinations, ophthalmologic exams and spinal imaging.
Research is underway at a number of institutions to develop a treatment for NF2 and its associated tumours. Hearing loss may occur gradually over months or years, or suddenly over a day or week. About half the people who develop NF2 have no family history of the disease.
