[1] Univ Birmingham Sch Med, Birmingham, AL USA
[2] Dept Obstet & Gynecol, Div Maternal Fetal Med, Birmingham, AL USA
[3] Univ Alabama Birmingham, Dept Genet, Birmingham, AL USA
[4] Univ Alabama Birmingham, Dept Pediat, KAUL 210,720 2nd Ave North, Birmingham, AL 35249 USA