HC Forum (R): a web site based on an international human cytogenetic database

Familial structural rearrangements of chromosomes represent a factor of mal formation risk that could vary over a large range, making genetic counselin g difficult. However, they also represent a powerful tool for increasing kn owledge of the genome, particularly by studying breakpoints and Viable imba lances of the genome. We have developed a collaborative database that now i ncludes data on more than 4100 families, from which we have developed a web site called HC Forum(R) (http://HCForum.imag.fr), It offers geneticists as sistance in diagnosis and in genetic counseling by assessing the malformati on risk with statistical models. For researchers, interactive interfaces ex hibit the distribution of chromosomal breakpoints and of the genome regions observed at birth in trisomy or in monosomy, Dedicated tools including an interactive pedigree allow electronic submission of data, which will be ano nymously shown in a forum for discussions. After validation, data are defin itively registered in the database with the email of the sender, allowing d irect location of biological material. Thus HC Forum(R) constitutes a link between diagnosis laboratories and genome research centers, and after 1 yea r, more than 700 users from about 40 different countries already exist.