[1] UNIV PAVIA, DIPARTIMENTO GENET & MICROBIOL, I-27100 PAVIA, ITALY
[2] CTR ETUD POLYMORPHISME HUMAIN, F-75010 PARIS, FRANCE
[3] CNR, IST GENET BIOCHIM & EVOLUT, I-27100 PAVIA, ITALY
[4] WASHINGTON UNIV, SCH MED, CTR GENET MED, ST LOUIS, MO 63110 USA