Dear Kobe,
Parkinson's Disease is "a degenerative neurological disease which
primarily impacts the specific part of the brain (substantia nigra)
which produces the neurotransmitter, dopamine." (Parkinson's Info,
<http://www.parkinsonsinfo.com/faq/>).
You asked about the transmission of Parkinson's Disease. However, it
is not know what causes this disease. The site Parkinson's Info adds
that "Some researchers believe it may result from toxins, head traumas
or strokes. Parkinson's Disease may also have a genetic link."
(SOURCE: Parkinson's Info, <http://www.parkinsonsinfo.com/faq/>).
Therefore, it is not clear at all that it is being "transmitted" - it
might not be genetic, or not in all cases. There are cases, in which
Parkinson's has been revealed to be a genetical disease:
"There are a few families that have a form of PD that is clearly
inherited. In these families, many people across several generations
are found to have PD. These families are very rare but they may help
us understand what causes the more common forms of PD that do not have
this very strong genetic cause. A gene that causes one such form of PD
has been found in a family from Italy."
(SOURCE: GenePD, <http://www.bu.edu/genepd/FAQ.htm>).
Another research site answers this question:
"Q: (11/21/03) Is Parkinson's disease a dominately or recessively
inherited disorder? (Anon.).
[...]
A: For the vast majority of patients, Parkinson's disease is not
inherited or genetic. Thus the question of whether it is dominant or
recessive does not apply.
For the extremely small number of people with genetic forms of PD, the
phenotypic expression of genetic parkinsonism is still being studied.
Although it is variable across individuals and across different
mutations, a few features are emerging as common to some of the
genetic forms of PD. These include younger age of onset (in the 40's
for the alpha-synuclein mutation and in the 20's for the parkin
mutation) than for idiopathic PD (whose mean age of onset is around 57
years), temporary improvement of symptoms after sleep ("sleep
benefit"), and marked improvement of symptoms with small doses of
levodopa.
The inheritance pattern for two of the mutations being studied is as
follows: autosomal dominant for the mutation in the alpha-synuclein
gene, and autosomal recessive for the parkin gene mutation. However,
many important questions remain unanswered, including the penetrance
of these mutations, i.e. how many people carrying the mutation
eventually develops symptoms of PD. Moreover, several genes implicated
in PD can have different mutations. Thus, genetic forms of PD remain
an important area of research, but we don't know enough about their
clinical expression to make specific clinical recommendations."
(SOURCE: Parkinson's Disease Foundation, Expert Resource Centre,
<http://www.pdf.org/Ask/kb.cfm?selectedItem=9800&returnURL=kb.cfm%3Fcategory%3D62>).
Because the research is so recent, and still ongoing, there are no
definitive answers here. Some of the carriers have a autosomal
recessive inheritance; the family from Italy mentioned before (as well
as others) have Autosomal dominant Parkinson's disease . Regarding
this family, you could read about the gene location (which is not
applicable for any type of PD), at:
A gene for Parkinson's Disease? (Davidson College undergraduate students' paper)
<http://www.bio.davidson.edu/courses/genomics/2001/madden/assignment1.html>.
GenePD, a site researching the issue of the role of genetics in
Parkinson's Disease, would have lots of interesting information for
you:
<http://www.bu.edu/genepd/index.htm>
Familial Parkinson's disease- frequently asked questions
<http://medweb.bham.ac.uk/clin_neuro/genetics/faq.html>
has much mroe information.
Maybe when you'll study in college, you'll advance PD research further
and find the genetical causes in other cases than the ones found.
My search terms:
"gene responsible for Parkinson's disease"
"Parkinson's disease" + terms that could assist in finding
information: genetic, etc.
Please contact me if you need any further clarification on this answer
before you rate it. |
