Since my daughter has Down syndrome, I get asked questions about health and what to expect for children with Down syndrome. This is my go-to resource. The American Academy of Pediatrics came out with a clinical health report for recommendations in 2011. It is very helpful. I often print out the entire report and take it to my daughter's doctor. Be sure to check out Appendix 1 for a chart on what to have checked at certain ages. You can find the link at:
http://pediatrics.aappublications.org/content/early/2011/07/21/peds.2011-1605.full.pdf+html