Schwannomatosis

Schwannomatosis is a rare form of neurofibromatosis that is primarily characterized by multiple schwannomas (benign tumors of the nervous system) in the absence of bilateral (affecting both sides) vestibular schwannomas. Signs and symptoms of the condition vary based on the size, location and number of schwannomas but may include pain; numbness; tingling; and/or weakness in the fingers and toes. Inherited forms of the disorder account for only 15 percent of all cases. In some of these families, schwannomatosis is caused by changes (mutations) in the SMARCB1 or LZTR1 genes; in other cases, the exact underlying cause is unknown. When inherited, the condition is passed down in an autosomal dominant manner with highly variable expressivity and reduced penetrance. Treatment is based on the signs and symptoms present in each person but may include medications and/or surgery.