http://www-medlib.med.utah.edu/WebPath/TUTORIAL/PRENATAL/PRENATAL.html
Information about prenatal diagnostic techniques. Includes information on chromosomal abnormalities.

http://www.ornl.gov/TechResources/Human_Genome/home.html
This is the home page of the Human Genome Project. There are links to sites related to specific conditions and chromosomes.

http://www.informatik.uni-rostock.de/HUM-MOLGEN/index.html
Mirror site for the above site.