Neurofibromatosis is any of a number of distinct genetic conditions that result in a high probability of tumor formation. However, all the conditions are caused by inheriting the single defective gene from a parent with the condition. However, in any given patient, the disease can be of varying severity due to the expression of other related genes. They fall into three categories:
- Type I – the tumors are generally benign, but can compress nerves and other tissues
- Type II – where the tumors form around the acoustic nerves, leading to hearing loss
- Schwannomatosis – where painful schwannomas grow around several different types of nerves