Previously, we have shown that the NF1 gene gives rise to multiple novel splice variants. In the present study, nine NF1 variants were quantified by real-time PCR in various human tissues. Some of these variants were expressed at low to moderate low levels and possible implications of these findings are discussed. Interestingly, two variants (NF1-ΔE4b and NF1-ΔE43) were shown to be highly expressed in specific tissues. NF1-ΔE43 lacks a nuclear targeting sequence and might be functionally different from full-length NF1. These novel NF1 splice variants might expand our understanding of the role of neurofibromin. © 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.