1. Down Syndrome Clinic, Instituto Nacional de Pediatría Mexico City Mexico
2. Department of Research Methodology Instituto Nacional de Pediatría Mexico City Mexico
3. Infectious Disease Research Center. Instituto Nacional de Enfermedades Respiratorias Mexico City Mexico
4. Instituto Nacional de Pediatría Mexico City Mexico
5. Down Syndrome Clinic, Hospital San Juan de Aragón Mexico City Mexico
6. Pediatric Endocrinology Service, Instituto Nacional de Pediatría Mexico City Mexico
7. Faculty of Sciences Universidad Nacional Autónoma de México Mexico City Mexico