Genetic mapping of consanguineous families in the Middle East
In the last several years, numerous genes have been implicated in the neurodevelopmental origins of autism; however, the vast majority of autism cases remain unexplained. My laboratory aims to help understand the genetic cause(s) of autism through the application of genetic research methods that trace shared ancestry in founder populations using novel, whole genome technologies.
Genetic mapping of consanguineous families (those that have recent shared ancestry, such as parents who are first or second cousins), especially those with multiple affected individuals, offer increased power over non-consanguineous families to identify genes causing inherited conditions. In addition, populations with high fertility rates, where families might average six or more children, simplify the genetic analysis and could allow gene mapping to be accomplished using just one or two extended families. Thus, my lab has engaged physician collaborators and a number of schools for children with autism in Turkey and countries of the Middle East to offer research participation to families with children with autism that demonstrate consanguinity or have multiple affected individuals.
Collaborating with health care providers and families in other parts of the world, such as the Middle East, brings similar challenges and rewards to conducting research in the US. Physicians are eager to find answers for the families they care for and parents struggle to provide their children with the best possible services available to them. The families there are strikingly similar to those we see in the US, with the same questions, concerns, frustrations and desires for their children. It is my hope that through our research activities in the region we can begin to answer some of these questions and shed more light on the needs of the children such that their medical and developmental service needs are met to the highest standards.
New technology is emerging in my lab that we are applying to our autism research and particularly to candidate research families enrolled from Turkey and the Middle East. This is a collaborative effort to characterize the complete genetic code of individuals whose autism appears to be inherited in their family. Many of these cases have thus far eluded our gene discovery efforts, but this next generation of DNA sequencing holds great promise. We will be comparing data on the “whole exome” – 2% of the genetic code that directly makes protein – and then data on the “whole genome” – all of the genetic code – from our research cases to normal controls using information available from the international “1000 Genomes Project”. We anticipate that this large bioinformatic undertaking will point us to key changes in the genetic code that cause autism. As my lab becomes more experienced with these techniques, we will begin to apply this to other groups of autism patients, including American families.
Christopher Walsh, MD, Ph.D.
Children’s Hospital Boston
The views expressed in this paper are those of the author(s) and do not necessarily represent the views of the NLM Family Foundation.