Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Causative gene for human "lobster claw" syndrome identified

21.05.2002


A new study using mouse "knockouts" shows that genes that control limb formation in insects have similar functions in mammals.



Split hand/foot malformation (SHFM) or ectrodactyly (the "lobster claw" anomaly), is a severe congenital malformation syndrome characterised by a profound median cleft of the hands and/or feet, typically associated with absence or fusion of the remaining fingers. This condition is quite frequent as about 6 cases of SHFM are observed for every 10,000 human births.

Several forms of SHFM are each associated with a different genetic mutation. One of the most frequent forms called Type I is associated with a specific region of human chromosome 7 that contains two homeobox genes, DLX5 and DLX6. These genes are similar to a gene in insects called distal-less that controls limb development. When this gene is defective in the fruit fly the distal part of the insect limb is missing. It was therefore assumed that DLX5 and DLX6 might have conserved this function through evolution and could have a role in vertebrate limb development. However, in spite of intensive searches for mutations of these genes in SHFM patients, no direct evidence was found to date on their involvement in mammalian limb development.


A research team led by Dr. Giovanni Levi from the Centre National de la Recherche Scientifique (CNRS) working in the Museum of Natural History in Paris and co-workers from the Italian Institute for Cancer Research (IST) supported by Telethon (Italy), has now generated knockout mice in which both the Dlx5 and Dlx6 genes have been inactivated through gene targeting and embryonic stem cells. These Dlx5/Dlx6 mutant mice have a limb defect that is very similar to that observed in SHFM1 patients. This finding, to be published in the June 2002 issue of genesis, is critical for an understanding of the molecular origin of the disease as it demonstrates that these are the genes responsible for the SFHM syndrome.

These studies should also warrant renewed efforts to find specific human mutations associated with DLX5 and DLX6 genes through genomic and mutational analyses. It is possible that knowledge of these genetic defects might permit early prenatal diagnosis of the disease. Furthermore, the availability of an animal model of the human disease will permit a molecular understanding of the etiology of SHFM1. Detailed studies of these mice will make it possible to understand how the genetic lesion is associated with a limb malformation in humans.

The data reported in Dr. Levi`s article show that in spite of the very different structure of insect and vertebrate limbs, the same genes control their development. This is further proof that the limb of a fly is homologous to a human limb.

Joanna Gibson | alphagalileo

More articles from Life Sciences:

nachricht Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology

nachricht Migrating Cells: Folds in the cell membrane supply material for necessary blebs
23.11.2017 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>