"Using a gene-chip technology, a team of clinicians, geneticists and statisticians looked at over one million polymorphic nucleotides, the letters A, C, G and T of the DNA sequence", said Dr. Kutalik. "Our analysis revealed that a single nucleotide polymorphism, or SNP, was present in a gene called IL28B, which encodes for interferon lambda. This was significantly associated with both natural and drug-induced clearance of the hepatitis C virus from the body. This polymorphism may exert its influence by modulating the expression level of the interferon lambda gene."
Individuals who carry the protective allele (letter) at this genetic locus are twice as likely to clear the virus and, even if they do not, they will respond to therapy in a sustained manner; the scientists say. "Individuals infected with the less malignant subtype of the virus and carrying no risk allele were five times more likely to respond than those who were infected with other subtypes and who carried at least one copy of the risk allele. Based on our results we can speculate that the interferon lamda gene is key to increasing the success of therapy, as such therapy could, in theory, compensate for the effect of the polymorphism. Phase 1B trials of interferon lamda therapy in patients with hepatitis C have already shown promising results", Dr. Kutalik said.
The scientists intend to follow up their work by focusing on a better understanding of the more complex characteristics of hepatitis C, including finding the genetic variants that are responsible for hepatitis C liver fibrosis. "This disease affects up to 300 million people worldwide. It is insidious, and often individuals are not awar
|Contact: Mary Rice|
European Society of Human Genetics