  |
|
|
|
This is the first in a series of articles relating to the issue of genetic testing for Huntington's Disease. Because there is so much more than clinical data to consider I want to be sure to provide you with as much medical, personal information as possible so as to give you a well rounded perspective of what this involves. This first article comes from Robin Bennett who was my genetic counselor when I went through testing this past year. What she explains so well in this booklet was exactly what she took me through in my own testing process.
Testing for Huntington's Disease: Making an Informed Choice The decision of whether or not to have testing for Huntington's disease (HD) is a very complex and personal one. Each individual in a family with HD will feel differently about testing. There are no right or wrong choices. It is important, however, that the person who is thinking about being tested make an informed choice. This pamphlet is intended to help the individual considering testing for HD reflect on some of the issues involved in testing and in dealing with the test results. Family, friends and professional support people may also find this material useful in supporting those considering testing. TRANSMISSION OF HUNTINGTON'S DISEASE: Huntington's disease is inherited in an autosomal dominant pattern. This means a person with HD has a 50:50 chance to pass the genetic change or mutation that causes HD to each son or daughter. A person who has not inherited this genetic change will not develop HD and cannot pass HD on to a child. DNA (deoxyribonucleic acid) makes up the genes which are the basic units of heredity. Genes contain the code of instructions which determines each individual's development, growth, and functions. Genes are located on threadlike structures called chromosomes, half from their father and half from their mother. There are 50,000 to 100,000 genes packaged on the chromosomes. Each gene occupies a particular location on a specific chromosome. The gene for HD is located on the tip of chromosome 4. Everyone has a specific piece of DNA on chromosome 4 that makes up the HD gene. This segment of DNA repeats in units of three and is called a CAG trinucleotide repeat. Tri means three and nucleotides are the building blocks of DNA. People who have inherited the gene change or mutation that causes HD have CAG trinucleotide that repeats and expands too many times. People who have the usual size range and fewer number of CAG repeats have not inherited HD.
The copyright of the article Testing for Huntington's Disease - Part One in Huntington's/Brain Disease is owned by Julie Sando. Permission to republish Testing for Huntington's Disease - Part One in print or online must be granted by the author in writing.
|
|
|
|
