Why do we have genes that cause genetic disorders?

Many genes are named for the disorders to which they have been linked. This can be very confusing. For example, the gene associated with hereditary hemochromatosis is called the “hemochromatosis gene.” This name implies that the gene exists for the sole purpose of causing disease, which of course is not the case. The normal function of a gene is to encode a protein, not cause illness. Disease occurs when genes are unable to work properly. The hemochromatosis gene actually codes for a membrane protein that works with other proteins to regulate iron absorption in cells. Like other single-gene disorders, hemochromatosis occurs when a gene is mutated in a way that prevents it from encoding a normal, functional protein product. See hereditary hemochromatosis disorder and gene profiles for more information about this condition.

Where can I learn more about genes associated with genetic disorders?

• Gene and Protein Database Guide -- A guide to resources for learning about genes and the proteins they encode. Access gene databases, nucleotide and protein sequence databases, sequence-similarity search tools, mutation resources, and molecular structure databases. Find step-by-step instructions for using some of these resources at the Bioinformatics Tools page.

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/assist.shtml