By Karla Gale
NEW YORK (Reuters Health) – American and German researchers reporting in the early online edition of Nature Genetics for January 30 have localized a genetic susceptibility to myocardial infarction (MI) to chromosome 14.
Dr. Ulrich Broeckel, of the Medical College of Wisconsin in Milwaukee, and colleagues identified 513 families in which at least two members had experienced MI before the age of 60 or severe, premature coronary artery disease, or both. Index patients were identified by screening patient charts from seven cardiac rehabilitation centers in Germany for those who had experienced an early MI.
The index patients, their parents and siblings were invited to participate in the study. Linkage analysis was conducted on blood samples from 1406 individuals.
The risk of MI mapped to a single region the includes approximately 150 genes. The maximum LOD score of 3.9 was significant (p = 0.00015), indicating that a major locus is involved, the authors note.
"When we estimated how much of the susceptibility is inheritable and how much is due to environmental factors, the overall heritable component was 40%," Dr. Broeckel told Reuters Health.
None of the genetic loci influencing such risk factors as lipoprotein a, diabetes mellitus, serum lipids, or arterial hypertension mapped to the same region on chromosome 14. "So it's probable that we're looking at new or additional mechanisms, which could improve our understanding of what leads to MI," Dr. Broeckel pointed out.
He stated that his research team is currently following up with these families in attempts to "localize the gene, better understand its function, see if there is any difference in the progression of disease [compared with the general population], and evaluate the risk for other family members who are as yet unaffected."
Once the specific gene is identified, it could be developed into a diagnostic test, Dr. Broeckel said. It could also represent a prime target for the development of new drugs.
Nat Genetics http://genetics.nature.com