Genometrics Section, Computational and Statistical Genomics Branch, Division of Intramural Research, NHGRI, NIH, Baltimore, MD, USA. Department of Pediatrics, University of California Davis, 4625 2nd Avenue, Research Building II, Sacramento, CA, 95817, USA. Department of Pediatrics, Division of Craniofacial Medicine, Seattle Children's Craniofacial Center, Seattle Children's Research Institute, University of Washington, Seattle, WA, USA. MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK. Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK. Craniofacial Unit, Oxford University Hospitals NHS Foundation Trust, Oxford, UK. West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's Hospitals NHS Foundation Trust, Birmingham, UK. Birmingham Craniofacial Unit, Birmingham Women's and Children's Hospitals NHS Foundation Trust, Birmingham, UK. Department of Clinical Genetics, Liverpool Women's NHS Foundation Trust, Liverpool, England, UK. Clinical Genetics Service, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK. National Institute of Pediatrics, Sofia Medical University, Sofia, Bulgaria. Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University of Sofia, Sofia, Bulgaria. National Genetic Laboratory, University Hospital of Obstetrics and Gynecology "Maichin Dom", Medical University of Sofia, Sofia, Bulgaria. Department of Neurosurgery, University Hospital 'St. Ivan Rilski', Medical University of Sofia, Sofia, Bulgaria. Department of Otolaryngology, Head and Neck Surgery, University of California Davis, Sacramento, CA, USA. Department of Neurosurgery, University of California Davis, Sacramento, CA, USA. Neuroscience Research Australia, University of New South Wales, Sydney, Australia. Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy. Section of Neurosurgery, Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy. Section of Experimental Biology, Department of Life Science and Public Health, Università Cattolica del Sacro Cuore, Rome, Italy. Department of Epidemiology, College of Public Health, The University of Iowa, 145 N Riverside Dr, S416 CPHB, Iowa City, IA, 52242, USA. Department of Pediatrics, Division of Medical Genetics, Carver College of Medicine, The University of Iowa, Iowa City, IA, USA. Gene and Environment Interaction Section, NHGRI, Bethesda, NIHMD, USA. Epidemiology Branch, Eunice Kennedy Shriver NICHD, NIH, Bethesda, MD, USA. Division of Genetics, NYS Department of Health, Wadsworth CenterAlbany, NY, USA. Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Austin, TX, USA. Department of Nutritional Sciences, University of Texas at Austin, Austin, TX, USA. Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA. National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA, USA. Department of Medical Microbiology and Immunology, Genome Center, and MIND Institute, University of California Davis, Davis, CA, USA. Department of Epidemiology, College of Public Health, The University of Iowa, 145 N Riverside Dr, S416 CPHB, Iowa City, IA, 52242, USA. paul-romitti@uiowa.edu. Department of Pediatrics, University of California Davis, 4625 2nd Avenue, Research Building II, Sacramento, CA, 95817, USA. sboyd@ucdavis.edu.