Health
Simple blood test diagnoses Parkinson's disease long before symptoms appear — A new research report appearing in the December issue of the FASEB Journal (http://www.fasebj.org) shows how scientists from the United Kingdom have developed a simple blood test to…
Early sign of Alzheimer's reversed in lab — One of the earliest known impairments caused by Alzheimer's disease - loss of sense of smell - can be restored by removing a plaque-forming protein in a mouse model of the disease,…
Parental controls on embryonic development? — When a sperm fertilises an egg, each contributes a set of chromosomes to the resulting embryo, which at these very early stages is called a zygote. Early on, zygotic genes are inert,…
Newly discovered heart stem cells make muscle and bone — Researchers have identified a new and relatively abundant pool of stem cells in the heart. The findings in the December issue of Cell Stem Cell, a Cell Press publication, show that…
BUSM researchers develop blood test to detect membranous nephropathy — Research conducted by a pair of physicians at Boston University School of Medicine (BUSM) and Boston Medical Centre (BMC) has led to the development of a test that can help diagnose…
New hip implants no better than traditional implants — New hip implants appear to have no advantage over traditional implants, suggests a review of the evidence published on bmj.com today…
Action needed to improve men's health in Europe — Policies aimed specifically at men are urgently needed to improve the health of Europe's men, say experts on bmj.com today…
Probiotics reduce infections for patients in intensive care — Traumatic brain injury is associated with a profound suppression of the patient's ability to fight infection. At the same time the patient also often suffers hyper-inflammation, due…
High blood sugar levels in older women linked to colorectal cancer — Elevated blood sugar levels are associated with an increased risk of colorectal cancer, according to a study led by researchers at Albert Einstein College of Medicine of Yeshiva University.…
Engineered botulism toxins could have broader role in medicine — The most poisonous substance on Earth - already used medically in small doses to treat certain nerve disorders and facial wrinkles - could be re-engineered for an expanded role in helping…
Where am I? > Home > News > Health

Abnormal protein makes Huntington's disease patients sick

Science Centric | 16 June 2010 13:59 GMT
Printable version A clip for your blog or website E-mail the story to a friend
Bookmark or share the story on your social network Vote for this article Decrease text size Increase text size
DON'T MISS —
Alzheimer's disease breakthrough
Alzheimer's disease breakthrough — CSIRO scientists have developed a new system to screen for compounds that can inhibit one of the processes that takes place…
Alzheimer's gene slows export of toxic amyloid-beta protein
Alzheimer's gene slows export of toxic amyloid-beta protein — The only known genetic risk factor for Alzheimer's disease slows down the brain's ability to export a toxic protein known…
More Health

An aggregating protein causes many of the symptoms of Huntington's disease, an incurable and frequently fatal brain disorder. Mosaic winner Ahmad Aziz discovered that the abnormal protein also aggregates in the hypothalamus, the part of the brain that regulates the autonomic nervous system and the endocrine system.

Ahmad Aziz investigated the severity and causes of a number of less well-known symptoms of Huntington's disease: weight loss, sleep disturbances and a poorly functioning autonomic nervous system. He established that many patients suffer from weight loss and sleeping problems. Abnormalities in the hypothalamus appear to account for some of these symptoms.

The hypothalamus was an obvious suspect for Aziz, as it regulates the autonomic nervous system and the endocrine system. Aziz established that certain nerve cells are lost in a part of the hypothalamus. In this part as well as in other parts of the hypothalamus abnormal protein aggregates were found. These hypothalamic nerve cells play an important role in the maintenance of body weight and a normal sleeping pattern.

Many of the patients investigated by Aziz get to sleep too late and wake up later in the morning than healthy people. Moreover, it appeared that the further the sleep rhythm is displaced, the more depressive the patients are. These patients also suffer from more cognitive abnormalities. The disruption of the sleeping rhythm could partly be due to a shift in the rhythm of the 'sleeping hormone' melatonin. That rhythm is regulated by the biological clock in the hypothalamus. Many Alzheimer's patients also have an abnormal sleep/wake rhythm. This can partially be corrected by light therapy and the administration of melatonin. Huntington patients might also benefit from such an approach.

Although the mutated Huntington's disease gene mainly causes damage in the brain, it is expressed in virtually all tissues, even though it does not cause damage everywhere. However, Aziz demonstrated that weight loss in the initial stages of Huntington's disease is not the consequence of other symptoms, such as hyperactivity, but is directly related to the mutation. This indicates that the cause must partly lie in the peripheral tissues, such as muscle and fat tissue. The defective gene probably causes damage there as well.

Huntington's disease is caused by a mutation in the huntingtin gene. In the mutated gene the DNA sequence C-A-G is repeated too often. Aziz's research reveals that weight loss and the number of CAG repeats are directly correlated: the greater the number of repeats, the greater the loss of weight.

The number of CAG repeats in the normal huntingtin gene can also influence the symptoms of the disease. This is because each person carries two copies of the huntingtin gene. In a normal gene there are 35 or less CAG repeats. Huntington patients have one normal gene and one defective gene with 36 or more repeats. Aziz discovered that the number of CAG repeats in both the normal gene and the defective gene is important for the rate at which the disease progresses. However, the effect of the normal gene is small and is mainly important for understanding how the disease develops and for a correct interpretation of future drug studies. It follows that such studies must take into account the differences in the number of CAG repeats in both genes.

Source: Netherlands Organisation for Scientific Research


Leave a comment
The details you provide on this page [e-mail address] will not be used to send unsolicited e-mail, and will not be supplied to a third party! Please note that we can not promise to give everyone a response. Comments are fully moderated. Once approved they will be posted within 24 hours.
Expand the form to leave a comment

RSS FEEDS, NEWSLETTER
Find the topic you want. Science Centric offers several RSS feeds for the News section.

Or subscribe for our Newsletter, a free e-mail publication. It is published practically every day.

Nanoparticles deliver their cargo, then disappearNanoparticles deliver their cargo, then disappear

— Medical researchers are looking at any number of new methods to get drugs to specific locations in the body. Some methods are efficient but less safe, while others…

Scientists use chemical from medicinal plant to fight HIVScientists use chemical from medicinal plant to fight HIV

— Like other kinds of cells, immune cells lose the ability to divide as they age because a part of their chromosomes known as a telomere becomes progressively shorter…

Tumours grow faster without blood-supply promoting moleculeTumours grow faster without blood-supply promoting molecule

— Dense networks of blood vessels thought to spur cancer's growth could actually hinder rather than promote tumour progression, according to a new study at the University…

Scientists first to sequence genome of cancer patientScientists first to sequence genome of cancer patient

— For the first time, scientists have decoded the complete DNA of a cancer patient and traced her disease - acute myelogenous leukaemia - to its genetic roots. A large…

Popular tags in Health: cancer · diabetes · malaria · obesity