Cerebral vasculopathy in a Chinese family with neurofibromatosis type I mutation

Neurofibromatosis type I (NF1) is a hereditary, autosomal dominant, neurocutaneous syndrome that is attributed to NF1 gene mutation. NF1 has been associated with scoliosis, macrocephaly, pseudoarthrosis, short stature, mental retardation, and malignancies. NF1-associated vasculopathy is an uncommon and easily-overlooked presentation. Examination of a Chinese family affected by NF1 combined with cerebral vessel stenosis and/or abnormality suggested a possible relationship between NF1 and vessel stenosis. To determine which NF1 gene mutation is associated with vascular lesions, particularly cerebral vessel stenosis, we examined one rare family with combined cerebral vessel lesions or maldevelopment. Vascular lesions were detected using transcranial Doppler sonography and digital subtraction angiography in family members. Next, denaturing high-performance liquid chromatography and sequencing were used to screen for NF1 gene mutations. The results revealed a nonsense mutation, c.541C>T, in the NF1 gene. This mutation truncated the NF1 protein by 2659 amino-acid residues at the C-terminus and co-segregated with all of the patients, but was not present in unaffected individuals in the family. Exceptionally, three novel mutations were identified in unaffected family members, but these did not affect the product of the NF1 gene. Thus the nonsense mutation, c.541C>T, located in the NF1 gene could constitute one genetic factor for cerebral vessel lesions.