ALTERATIONS OF MICROSATELLITES IN NEUROFIBROMAS OF VON RECKLINGHAUSENS DISEASE

von Recklinghausen's disease, or type 1 neurofibromatosis, a common fa milial tumor syndrome, is characterized by the occurrence of multiple benign neoplasms of nerve sheath cells, The disease is caused by germ- line mutations of the NF1 gene, which encodes a member of the GTPase-a ctivating superfamily of Ras regulatory proteins. We analyzed 5 dinucl eotide repeat loci in DNAs from neurofibromas and matched normal skin from 16 NF1 patients, Eight cases (50%) manifested microsatellite alte rations, Expansions or compressions of dinucleotide repeats were obser ved at one locus in four cases and at two loci in one case, Banding pa tterns compatible with the loss of a microsatellite allele were observ ed in four cases, including one that also presented microsatellite ins tability, The surprisingly high frequency of microsatellite alteration s suggests that the NF1 gene or another gene(s) contributing to the pa thogenesis of neurofibromas might be directly or indirectly implicated in the control of genomic integrity.