[1] Washington & Lee Univ, Coll Arts & Sci, Lexington, VA 24450 USA
[2] Johns Hopkins Univ, Sch Med, Dept Genet Med, Baltimore, MD USA
[3] Johns Hopkins Univ, Sch Med, Dept Gynecol & Obstet, Div Maternal Fetal Med, Baltimore, MD 21205 USA
[4] Johns Hopkins Sch Med, Dept Pediat, Div Dev Med, Baltimore, MD USA
[5] Kennedy Krieger Inst, Phelps Ctr Cerebral Palsy & Neurodev Med, Baltimore, MD USA
[6] Kennedy Krieger Inst, Ctr Autism & Related Disorders, Baltimore, MD USA
[7] Kennedy Krieger Inst, Ctr Dev & Learning, Baltimore, MD USA
[8] Hlth Serv Children Special Needs, Washington, DC USA
[9] Johns Hopkins Univ, Neurosci Intens Care Nursery Program, Sch Med, Baltimore, MD USA