Analysis of CpG C-to-T mutations in neurofibromatosis type 1

✍ Scribed by Sofia Krkljus; Corinne R. Abernathy; Jennifer S. Johnson; Charles A. Williams; Daniel J. Driscoll; Roberto Zori; Heather J. Stalker; Sonja A. Rasmussen; Francis S. Collins; Boris G. Kousseff; Lisa Baumbach; Margaret R. Wallace

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 83 KB
• Volume: 11
• Category: Article
• ISSN: 1059-7794
• DOI: 10.1002/(sici)1098-1004(1998)11:5<411::aid-humu11>3.0.co;2-2

✦ Synopsis

Neurofibromatosis type 1 (NF1) is a dominant disorder caused by mutations in the NF1 gene; approximately 100 NF1 gene mutations have been published. The CpG C-to-T transition is a frequent mutation mechanism in genetic disorders. To estimate its frequency in NF1, we employed a PCR-restriction digestion method to examine 17 CpGs in 65 patients, and also screened for a CpG nonsense transition (R1947X) that occurs in 1-2% of patients. The analysis revealed disease-related CpG C-to-T transitions (including a nonsense mutation that may be as frequent as R1947X) as well as a benign variant and another mutation at a CpG. Four patients showed CpG mutations in analysis of 18 sites (17 surveyed by restriction digest, plus the R1947X assay), including three C-to-T transitions and one C-to-G transversion. These 18 sites represent one-fifth of the 91 CpGs at which a C-to-T transition would result in a nonsense or nonconservative missense mutation. Thus, it is feasible that the CpG mutation rate at NF1 might be similar to that seen in other disorders with a high mutation rate, and that recurrent NF1 mutations may frequently reside at CpG sites.