Clinical application of genetic polymorphism in neurofibromatosis type 1.

The authors report the study of DNA polymorphic sequences, 5 intragenic and 5 flanking the NF1 gene, in 87 Italian NF1 families for a total of 142 affected individuals and 204 non-affected relatives. All PCR-based analyses are easy and simple to perform, and require small amounts of DNA. The non radioactive method used is sensitive, rapid, and has low background. All subjects were informative for at least 2 markers. The use of linkage study to familial cases allowed us to exclude the diagnosis prenatally in two fetuses, and to confirm or exclude diagnosis in those relatives with clinical signs, but not fulfilling the international diagnostic criteria. Furthermore indirect analysis permitted the detection of large gene deletions by loss of heterozygosity of one or more DNA markers in three out of 47 sporadic cases.