A Weill Cornell Medical College study that analyzed the DNA of Qatar's native population has discovered genetic variations that could help reduce the prevalence of a variety of debilitating hereditary disorders.
Researchers at Weill Cornell Medical College in Qatar (WCMC-Q) and their counterparts in New York, working with colleagues from Cornell University in Ithaca and Hamad Medical Corporation, identified 37 genetic variants in 33 genes known to play causal roles in a total of 36 diseases, including such devastating conditions as cystic fibrosis, sickle cell anemia and muscular dystrophy. The study, published online in November in the journal Human Mutation, points the way to more comprehensive screening for a host of inherited diseases, which could significantly reduce their incidence among the Qatari population.
The project sequenced the DNA of 100 Qatari nationals representing the three major ethnic subgroups of the country — the Bedouin, those of Persian-South Asian descent, and those of African descent. By analyzing participants' exomes — important sections of the DNA containing the code that is translated into proteins — and comparing them to the genetic data of people in the worldwide 1000 Genomes Project (1000G), the researchers were able to identify the variations that cause disease in Qatar.
All of the conditions targeted in the study were so-called Mendelian diseases. Named for Gregor Mendel, the 19th century researcher widely regarded as the founder of genetic science, Mendelian diseases are those caused by a single mutated gene and are also known as monogenic disorders.
"The reason this is relevant for Qatar is that the structure of the society encourages a high degree of consanguineous marriage, so the frequency of these monogenic diseases is quite high," said Dr. Ronald Crystal, chairman of genetic medicine at Weill Cornell Medical College in New York, who is leading a group of projects investigating the Qatari genome.
Currently, pre-marital counseling in Qatar screens for four genetic variations out of the 37 identified by the study, so incorporating the newly discovered variations into the screening process could have a significant impact.
"With more comprehensive screening, people will be able to make more informed choices about whether they feel it is safe to have children together," Dr. Crystal said. "Alternatively, it is possible to screen the fertilized eggs for variations that cause disorders before they are implanted."
Dr. Juan L. Rodriguez-Flores, a post-doctoral associate in the Department of Genetic Medicine in New York and the study's first author, and second author Dr. Khalid Fakhro, a postdoctoral associate in genetic medicine in Qatar, were co-lead principal investigators on the study.