Scanning the first part of the neurofibromatosis type 1 gene by RNA-SSCP: identification of three novel mutations and of two new polymorphisms.

Neurofibromatosis type 1 (NF1) of von Recklinghausen is a common autosomal dominant disorder, characterized by peripheral neurofibromas, café-au-lait spots and Lisch nodules of the iris. The high mutation rate at the NF1 locus results in a wide range of molecular abnormalities. We have scanned 14 different exons from the first part of the NF1 gene using the RNA-single strand conformation polymorphism (RNA-SSCP) method in a series of 40 NF1 patients. Three novel mutations, two nonsense and one missense, and two polymorphisms have been detected in familial cases. Genotype-phenotype correlations have been investigated, but no particular association has been detected. After this screening, the majority of NF1 chromosomes has not yet been characterized, confirming the difficulty in detecting the defect underlying NF1 in most families, even following extensive DNA analysis.