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.