[1] CNR,INST EXPTL MED,VIA C MARX 15,I-00137 ROME,ITALY
[2] UNIV URBINO,CHAIR GENET,I-61029 URBINO,ITALY
[3] UNIV TOR VERGATA,DEPT CELL BIOL & PUBL HLTH,ROME,ITALY
[4] UNIV ROME LA SAPIENZA,CTR PRENATAL DIAG,I-00185 ROME,ITALY
[5] UNIV ROME LA SAPIENZA,DEPT OBSTET & GYNECOL 2,I-00185 ROME,ITALY