What
exactly is Huntington’s disease? Huntington’s disease (HD) is an inherited
neurological condition that affects both the brain and the nervous system. Some
of the symptoms people with HD may exhibit are: involuntary muscle movements,
slurred speech, depression and anxiety, emotional control issues, and
difficultly with thought processes. Once the first symptoms begin normally
people live 15 to 20 years with the disease slowly progressing. HD is caused by
an inherited change in a huntingtin gene. The huntingtin gene is the gene that
is associated with HD. Each parent passes on one of the two huntingtin gene
copies they have to their child. If a person has a faulty huntingtin gene copy
then they are either affected or pre-symptomatic. This person has a 50% chance
that this faulty gene will be passed on to their child.
People can get pre-symptomatic
genetic testing done in order to see if they have the faulty huntingtin gene.
This means they will test to see how many CAG repeats are in their huntingtin
gene. A blood sample is taken from the subject in order to inspect the DNA. The
first step of the test is to do polymerase chain reaction (PCR) in order to
isolate DNA and make copies. From the millions of copies made from PCR, the DNA
fragments need to be separated by Gel Electrophoresis in order to analyze them.
In the huntingtin gene if there are
less than 26 repeats of CAG triplet then that is considered the normal range
and not faulty, and this person would not have HD. The same goes for the range
27-35 repeats. If a person has 36-39 CAG repeats it is very likely that the
person will develop HD. However, it might develop at a later age with less
severe conditions, or they might not develop HD at all. Yet if there are more
than 40 CAG repeats that person will almost certainly develop HD.
As of right now there is no
treatment or cure for HD, but research is ongoing in order to help manage the
symptoms. Personally knowing a family that is affected by Huntington’s disease,
I feel that more people should be made aware about HD and it’s affects. This is
an important cause that people should know about.
It's really devastating. My cousin was diagnosed last year, and it's been awful for him. The family, of course, was worried that more would have it, but it turns out that he likely inherited a mutatant form of his fathers long, but not quite HD-long allele.
ReplyDelete