Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCSD researchers identify chromosome location for 2nd form of Joubert syndrome

04.09.2003


Physicians may be a step closer to pre-natal diagnosis of a rare genetic disorder called Joubert syndrome. This condition, present before birth, affects an area of the brain controlling balance and coordination.



New findings from the University of California, San Diego (UCSD) School of Medicine have identified chromosome 11 as a second site for a gene or genes that cause Joubert syndrome, a disorder that affects about 1 in 30,000 individuals. Prior to this study, chromosome 9 had been the only known site with gene mutations causing the disorder.

The new study, published online in the September issue of the American Journal of Human Genetics, focused on three Middle Eastern families whose relatives had inter-married and passed the genetic defect to several family members.


Characterized by absence or underdevelopment of a brain region called the cerebellar vermis, and by a malformed brain stem, Joubert syndrome affects individuals to varying degrees across the spectrum of motor and mental development. Its most common features include lack of muscle control and decreased muscle tone; an abnormal breathing pattern called hypernea, in which babies pant; abnormal eye and tongue movements; and mild or moderate retardation. The type of Joubert syndrome now traced to chromosome 11 also includes eye or kidney problems, in addition to the classical symptoms associated with the disorder.

“The hunt for genes for this syndrome has been extremely slow and none are currently known, due to the rarity of the syndrome,” said the study’s senior author, Joseph Gleeson, M.D., UCSD assistant professor of neurosciences. “The main problem in identifying genes has been the small number of patients appropriate for genetic analysis.”

This led Gleeson’s team to an intensive patient recruiting effort and a change in the way the analysis was being performed.

Joubert syndrome is inherited in an autosomal recessive manner, which means that both parents carry the mutant version of the gene, while showing no signs of the disease themselves. To increase their subject pool for research, the Gleeson team focused on the Middle East, where families are larger and inter-marriage between cousins is an accepted custom. Working with collaborators in Oman, the United Arab Emirates, Saudi Arabia, Jordan and Pakistan, the UCSD researchers obtained DNA samples from affected and unaffected individuals in 20 families.

Using sophisticated genetic screening tools, the researchers identified a common genetic region in seven children from three affected families who displayed the form of Joubert syndrome with eye and kidney problems. These patients included a northern Pakistani child of first cousins, who displayed visual impairment and kidney cysts in addition to the characteristic breathing abnormality and muscle coordination problem. Two of six children of first cousins from the United Arab Emirates, exhibited Joubert features such as brain malformations (as revealed on an MRI scan), impaired vision, jerky eye movements and a malformed retina. Three children from another United Arab Emirates family experienced panting respirations, balance problems, retinal dystrophy and moderate visual impairment.

The study’s authors noted that the variability of symptoms in the affected individuals suggests that there may be genetic modifiers that influence the disease severity and expression of symptoms.

Gleeson, who has studied Joubert syndrome for several years, noted “parents of affected children are just craving for information, to understand the basis for this disorder and something about the prognosis. The most heart wrenching thing is parents who are reluctant to get pregnant again because they have had a single child with this condition.”

He added that the possibility of developing a genetic screening test gives his group an additional incentive to discover the gene as soon as possible.

“We don’t yet know the exact genes involved; this is an incremental step,” Gleeson said. “But, we’re getting closer to providing the information these parents so desperately want.”

In addition to Gleeson, additional researchers include first-author Lesley C. Keeler, M.S., Sarah E. Marsh, M.S., Esther P. Leeflang, Ph.D., Neurogenetics Laboratory, UCSD Division of Pediatric Neurology; Christopher G. Woods, M.D., Molecular Medicine Unit and Yorkshire Clinical Genetics Service, St. James’ University Hospital, Leeds, United Kingdom; and Aithala Gururaj, Lihadh Al-Gazali, DCH, Laszlo Sctriha, M.D., Ph.D., Department of Pediatrics, United Emirates University, Al Ain, UAE.

The study was performed collaboratively with the Marshfield Center for Genetics in Wisconsin and funded by the March of Dimes.

Sue Pondrom | UCSD
Further information:
http://health.ucsd.edu/news/2003/09_03_Gleeson.html
http://gleesongenetics.ucsd.edu/
http://www.joubertsyndrome.org/index.htm

More articles from Health and Medicine:

nachricht Cholesterol-lowering drugs may fight infectious disease
22.08.2017 | Duke University

nachricht Once invincible superbug squashed by 'superteam' of antibiotics
22.08.2017 | University at Buffalo

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>