[1] Newcastle Univ, Inst Human Genet, Int Ctr Life, Newcastle Upon Tyne NE1 3BZ, Tyne & Wear, England
[2] Childrens Hosp Philadelphia, Div Neurol, Philadelphia, PA 19104 USA
[3] Childrens Hosp Philadelphia, Div Pulm Med, Philadelphia, PA 19104 USA
[4] Childrens Hosp Philadelphia, Div Gastroenterol Hepatol & Nutr, Philadelphia, PA 19104 USA
[5] Case Western Reserve Univ, Metrohlth Med Ctr, Div Pediat Pulm Med, Cleveland, OH USA
[6] Duke Univ, Dept Community & Family Med, Div Phys Therapy, Durham, NC USA
[7] Univ Pittsburgh, Dept Neurol Mol Genet & Biochem, Pittsburgh, PA USA
[8] Dept Vet Affairs Med Ctr, Pittsburgh, PA USA
[9] Cincinnati Childrens Hosp, Med Ctr, Div Cardiol, Cincinnati, OH USA
[10] Cincinnati Childrens Hosp, Med Ctr, Div Pediat Gastroenterol Hepatol & Nutr, Cincinnati, OH USA
[11] Univ Calif Davis, Dept Phys Med & Rehabil, Davis, CA 95616 USA
[12] Univ Rochester, Dept Neurol, Rochester, NY USA
[13] Baylor Coll Med, Sch Allied Hlth Sci, Houston, TX 77030 USA
[14] Childrens Hosp, Dept Orthopaed Surg, Boston, MA 02115 USA
[15] Ctr Dis Control & Prevent, Natl Ctr Birth Defects & Dev Disabil, Atlanta, GA USA