Clinical epidemiology of NF2-related schwannomatosis.

The epidemiology of NF2-related schwannomatosis (NF2) has only been possible to delineate after the separation of NF2 from the more common nerve sheath-predisposing tumor condition NF1 in 1987. Two groups have published data on the birth incidence and prevalence of NF2 in the United Kingdom and Finland. The most recent estimate from the United Kingdom for NF2 cases ascertained from the Manchester region of England (population=4.8 million) and from across the United Kingdom gave a point prevalence of 1 in 50,500 and a birth incidence of 1 in 27,956. NF2 usually presents with bilateral vestibular schwannoma but may also present with meningioma or spinal tumor before a VS diagnosis or with a unilateral VS and other tumors and rarely with a unilateral VS alone. Molecular testing is now extremely helpful in early diagnosis, especially in childhood. This chapter summarizes the clinical epidemiology of NF2, differentiating the condition from the overlapping non-NF2-related schwannomatoses.