Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Genetic cause of speech defect discovered

20.10.2005


Nine-year-old boy from northern Alberta tested and found to have genetic abnormality; first time it’s been identified by researchers



Researchers at the University of Toronto (U of T), Capital Health’s Stollery Children’s Hospital in Edmonton, Toronto’s Hospital for Sick Children and their international collaborators have discovered a genetic abnormality that causes a type of language impairment in children – a discovery that could lead to isolating genes important for the development of expressive language.

A study published in the Oct. 20 issue of the New England Journal of Medicine outlines the discovery of a genetic abnormality in a nine-year-old boy with learning difficulties and speech problems from northern Alberta. By using some of the latest genetic screening methods designed to look for differences in the amount of DNA in particular chromosomes, the researchers discovered that the boy carries additional copies (termed duplication) of around 27 genes on chromosome 7. This is only the second instance of the identification of a single chromosome region linked to specific language impairment.


The boy can understand what is said to him at the level of a seven-year-old but his expressive language and speech are at the level of a two-and-a-half-year-old. "Our results show that changes in the copy number of specific genes can dramatically influence human language abilities," says senior author Lucy Osborne, a U of T professor of medicine. "Based on our findings, we are expanding the study to assess the frequency of this DNA duplication in children with expressive language delay."

The chromosome 7 region that is duplicated in this boy is exactly the same as that which is deleted in Williams-Beuren syndrome (WBS), a neurodevelopmental disorder. While patients with WBS exhibit mild mental retardation, they also have strength in expressive language, alongside very poor performance in tasks involving spatial construction, such as drawing. In striking contrast, this patient could form virtually no complete words but showed normal spatial ability. "For example, if asked to tell us what animal has long ears and eats carrots, he could only pronounce the r, of the word rabbit but was able to draw the letter on the blackboard and add features such as whiskers," Osborne says.

This mutation – an addition of 1.5 million DNA base pairs – was predicted several years ago to exist by Osborne and her collaborator Stephen Scherer of The Hospital for Sick Children and U of T. "While estimated to be present in more than a half million people worldwide, the duplication has evaded detection since the disease was unknown until now, but also because finding this type of mutation is technically challenging," explains Martin Somerville, director of the Molecular Diagnostic Laboratory at the Stollery Children’s Hospital. Uncovering the duplication sheds light on which genes are necessary for normal expressive language. "Language impairment was thought to be caused by the interaction of multiple genes on different chromosomes, but in this case our discovery implicates a specific location on chromosome 7," Somerville says. "In order to know how to treat a disease you have to know its cause, so this is a significant step in the right direction."

Other authors on the study are Edwin Young and Wayne Loo, Institute of Medical Science and Department of Molecular & Medical Genetics, University of Toronto; Stephen Bamforth and Margaret Lilley, Department of Medical Genetics, University of Alberta; Carolyn Mervis and Ella Peregrine, Department of Psychological and Brain Sciences, University of Louisville; Miguel del Campo and Luis Pérez-Jurado, Unitat de Genética, Departament Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona; and Colleen Morris, Department of Pediatrics, University of Nevada School of Medicine; and Eul-Ju Seo and Stephen Scherer, Program in Genetics & Genomic Biology, The Hospital for Sick Children, Toronto and U of T.

Karen Kelly | EurekAlert!
Further information:
http://www.utoronto.ca

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>