Natural history of neurofibromatosis type 2 with onset before the age of 1 year.

Neurofibromatosis type 2 (NF2) with onset before the first year of life has been anecdotally reported in the literature. We (a) prospectively (years 1997-2012) followed up three unrelated NF2 children, all harbouring NF2 gene mutations whose onset of disease was before age 1 year, and (b) systematically reviewed published reports on NF2 in the youngest age group (i.e. onset <1 year). The present three children had (1) small (<1 cm), bilateral vestibular schwannomas (VSs) detected (as an incidental finding) at magnetic resonance imaging (MRI) by the age of 4 to 5 months that were asymptomatic for 10 to 14 years, with sudden and rapid (<12 months) progression in two cases at the age of 11 and 15 years, respectively; (2) development of large numbers of skin NF2 plaques mainly in atypical locations (i.e. face, hands, legs and knees), which reverted to normal skin appearance at the time of VSs progression; (3) lens opacities (n = 1) and NF2 retinal changes (n = 2) detected as early as age of 3-4 months; (4) diffuse (asymptomatic) high signal lesions at brain MRI in the periventricular regions (alike cortical dysplasia); and (5) unaffected first-degree relatives who did not harbour NF2 gene abnormalities. This represents the youngest NF2 group with the longest prospective follow-up so far reported. NF2 may present as a congenital form with bilateral VSs presenting as early as the first months of life and with natural history different to that which occurs in classical NF2.