NF2 and schwannomatosis: Some incidences of solitary VS appear to cluster within families.11,12 Moreover, that phenotype and clinical outcome variability between, and within, NF2-related and non-NF2-related schwannomatosis-affected families suggests the existence of genetic variants that modify VS risk and clinical course.13,14 It is hypothesized that the missing heritability and variable presentation observed in VS cases can be explained, at least in part, by common low-penetrance, small-effect-size inherited genetic variants.