[1] New Jersey State Dept Hlth, Div Family Hlth Serv, Special Child Hlth & Early Intervent Serv, Trenton, NJ 08625 USA
[2] Cts Dis Control & Prevent, Natl Ctr Birth Defects & Dev Disabil, Atlanta, GA USA
[3] Childrens Hosp Philadelphia, Dept Pediat, Philadelphia, PA 19104 USA
[4] Univ Penn, Perelman Sch Med, Philadelphia, PA 19104 USA
[5] Cohen Childrens Med Ctr, Dept Pediat, New Hyde Pk, NY USA
[6] Univ Med & Dent New Jersey, Robert Wood Johnson Med Sch, Dept Pediat, New Brunswick, NJ 08903 USA
[7] Duke Univ, Duke Clin Res Inst, Durham, NC USA
[8] Duke Univ, Dept Pediat, Durham, NC 27706 USA