Chromosome imbalances in familial gliomas detected by comparative genomic hybridization

Familial occurrence of gliomas, in the absence of well-defined hereditary m ultisystem disorders, is reported occasionally. We describe 17 families tha t have been afflicted with two or more gliomas but do not raise suspicion o f other inheritable syndromes. The families were identified among 369 conse cutive glioma patients operated at the Tampere University Hospital during 1 983-1994. We applied comparative genomic hybridization (CGH) analysis on 21 gliomas occurring in these 17 families. The most frequent genetic alterati ons, detected in over 20% of the tumors, were losses of 6q, 10, 4q, 9p and gains of 7, 19, 20q, Ip. We compared the chromosomal alterations detected i n the familial gliomas to those reported previously on 209 sporadic gliomas in nine different CGH studies. In this comparison, the familial gliomas mo re often showed losses of chromosome arms 4q and 6q and gains of Ip and 22q . The most frequent losses (9/21 tumors) in the familial gliomas resided on chromosome arm 6q (P = 0.005, Fisher's exact test; with Bonferroni correct ion, P = 0.04). The loss of 6q was also the most common intrafamilial aberr ation, present in four separate gliomas belonging to two families. The mini mal common area of loss on this chromosome resided at 6q14-16. In conclusio n, we have found several characteristic aberrations by CGH in the familial gliomas and we present new chromosomal regions possibly involved in the fam iliar predisposition to gliomas. (C) 2000 Wiley-Liss, Inc.