Epidemiology

Familial sources, genetic predisposition seen in clustering of hepatitis C

Last Updated: 2008-09-17 12:40:21 -0400 (Reuters Health)

By Will Boggs, MD

NEW YORK (Reuters Health) - Intrafamilial transmission of hepatitis C virus (HCV) and genetic predisposition to infection may explain the familial component of hepatitis C in endemic countries, according to a report in the September issue of Gut.

HCV seropositivity is significantly higher "within families than expected by chance, even after adjustment for known risk factors for infection," Dr. Sabine Plancoulaine from INSERM, Paris, France told Reuters Health. At least a part of this "could be explained by host genetic predisposition to HCV infection."

Dr. Plancoulaine and colleagues investigated familial clustering of HCV infection in a population living in rural Egypt, a highly endemic area. The study involved 3994 subjects from 475 familial clusters.

Evaluation of serological status showed highly significant father-child, mother-child, and sibling-sibling associations, the authors report, with odds ratios ranging from 3.4 to 9.3. A weaker association was seen between spouses, but age was strongly associated with the risk of HCV infection.

Viral strain similarity was significantly more frequent for patients from the same family than for unrelated subjects, the researchers note.

"The respective contribution of direct HCV transmission between relatives by close contacts or exposure to an unidentified common source of virus to the intrafamilial clustering of viral strains remains to be determined by an in-depth community study," the investigators say. "

"We are currently performing the segregation analysis which will allow us to determine whether or not there is a genetic part in the familial correlation for HCV infection and identify the genetic model (dominant, additive, or recessive) underlying this effect," Dr. Plancoulaine said. "The preliminary results are very encouraging and we plan to publish them by the end of this year."

The next step will be "to perform a linkage analysis for HCV infection to map the genetic effect within the whole genome," Dr. Plancoulaine added. "Genotyping of the informative families is ongoing. We hope to be able to publish the results next year."

Gut 2008;57:1268-1274.