Cranio-Facial Changes the in Patients with Huntington Disease, A Review Article

Huntington's disease (HD) is a rare autosomal
dominant sever and usually fatal chronic neurodegenerative
illness with prevalence of 5.96 to 13.7 per 100000. The primary
pathology is the precipitation of huntingtin protein in the neurons
due to the presence of multiple CAG repeat in the N terminal of
the HTT gene on the short arm of chromosome 4. Classically this
is well known to primarily affect the caudate nucleus the largest of
the basal ganglia. This manifests radiologically by shrinkage of the
caudate nucleus with secondary dilatation of ventricular system.
This however cannot explain the fact that the HD patients show a
multitude of psychiatric and cognitive symptoms in addition to
chorea. But it may be explained by the recent studies that show the
basal nuclei are involved in limbic and emotional control in
addition to their motor function. In order to review evidence of
structural basal ganglia changes and their relation to clinical
manifestations in patients with HD we conducted a web based
search for published literature in the topic using pubmed and
google scholar.
The review of the literature showed that the initial changes in
HD happen in the caudate nucleus. Other parts of the striatum
such as the putamen and globus pallidus are also affected,
particularly following disease progression, with additional proof
of thalamic changes. Such structural changes, in the striatum, for
example, have been associated with specific cognitive deficits
including attention, working memory and executive functions.
Interestingly studies reported that MRIs are able to detect these
changes long before clinical manifestation of HD.
We concluded that most of the components of the basal ganglia
are reduced in size in HD. This volume reduction is evident years
before the onset of the disease. The magnitude of volume reduction
is directly related to the severity of the disease. These changes may
be used to predict the onset and prognosis of disease and to
monitor the response to treatment.