The NIH has great information on ALP that can be found at the link below:
http://www.nlm.nih.gov/medlineplus/ency/article/003470.htm
Lab Tests On-line has good info, too:
http://www.labtestsonline.org/understanding/analytes/alp/glance.html
WebMD:
http://www.webmd.com/digestive-disorders/alkaline-phosphatase
For information on Shwachman-Diamond Syndrome check out Shwachman-Diamond America