GERMLINE MUTATIONS IN THE VHL GENE IN PATIENTS PRESENTING WITH PHEOCHROMOCYTOMAS

It has been shown that an appreciable percentage of patients presentin g with primary, apparently sporadic phaeochromocytomas may in fact hav e von-Hippel-Lindau (VHL) disease. In order to investigate this, we re trospectively screened 68 patients, who had been operated on for phaeo chromocytomas, for the presence of germline mutations in the vhl gene. DNA was isolated from peripheral-blood leukocytes and used to screen the entire coding sequence and the intron-exon boundaries of the vhl g ene for mutations, using a PCR-based SSCP strategy. When an abnormal p attern was found in the SSCP analysis, sequence analysis was carried o ut. We found SSC variants in the vhl gene in 8 of the 68 patients. Of 6 patients, 2 turned out to be related (an uncle and his nephew), and they carried the same mis-sense mutation: R64P. In 4 other patients, m is-sense mutations, P25L, L63P, G144Q and II47T, were also identified. None of these mutations has been described, and 3 of them (P25L, L63P and R64P) are located closer to the N terminus of the vhl protein tha n any reported vhl mutation. In the remaining 2 cases, the mutations w ere localized not in the coding sequence but in the intronic sequence (but not within splice sites), adjacent to the exon, so they were prob ably not related to the disease. Our results show that a relatively hi gh proportion (6/68, or 8.8%), though not as high as the 20% reported earlier, of patients with apparently sporadic phaeochromocytomas may c arry germline mutations in the vhl gene. (C) 1998 Wiley-Liss, Inc.