Featured Research

from universities, journals, and other organizations

Genetic Cause Of Speech Defect Discovered

Date:
October 22, 2005
Source:
University of Toronto
Summary:
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.

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 P้rez-Jurado, Unitat de Gen้tica, Departament Ci่ncies 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.

###

This study was supported by grants from the Canadian Institutes of Health Research (CIHR) and the Sick Kids Foundation, the Spanish ministries of health and science and technology, Genome Canada/Ontario Genomics Institute, the National Institute of Neurological Disorders and Stroke and the National Institute of Child Health and Human Development. Scherer is a CIHR investigator and an international scholar of the Howard Hughes Medical Institute. Osborne is a CIHR research scholar.



Story Source:

The above story is based on materials provided by University of Toronto. Note: Materials may be edited for content and length.


Cite This Page:

University of Toronto. "Genetic Cause Of Speech Defect Discovered." ScienceDaily. ScienceDaily, 22 October 2005. <www.sciencedaily.com/releases/2005/10/051022234552.htm>.
University of Toronto. (2005, October 22). Genetic Cause Of Speech Defect Discovered. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2005/10/051022234552.htm
University of Toronto. "Genetic Cause Of Speech Defect Discovered." ScienceDaily. www.sciencedaily.com/releases/2005/10/051022234552.htm (accessed April 18, 2014).

Share This



More Mind & Brain News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Study On Artists' Brain Shows They're 'Structurally Unique'

Study On Artists' Brain Shows They're 'Structurally Unique'

Newsy (Apr. 17, 2014) — The brains of artists aren't really left-brain or right-brain, but rather have extra neural matter in visual and motor control areas. Video provided by Newsy
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) — A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Are School Dress Codes Too Strict?

Are School Dress Codes Too Strict?

AP (Apr. 16, 2014) — Pushing the limits on style and self-expression is a rite of passage for teens and even younger kids. How far should schools go with their dress codes? The courts have sided with schools in an era when school safety is paramount. (April 16) Video provided by AP
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins