Epidemiology

Monosomy X linked to primary biliary cirrhosis

Last Updated: 2004-02-12 18:30:20 -0400 (Reuters Health)

NEW YORK (Reuters Health) - The frequency of monosomy X is significantly higher in women with primary biliary cirrhosis than in healthy women or those with chronic hepatitis C, new research indicates.

PBC is known to affect women more often than men with a ratio of about 9 to 1.

The study findings suggest that "haploinsufficiency for specific X-linked genes leads to female susceptibility to primary biliary cirrhosis," lead author Dr. Pietro Invernizzi, from the University of Milan in Italy, and colleagues note.

The findings, which are reported in the February 14th issue of The Lancet, are based on a study of 100 women with primary biliary cirrhosis, 50 with chronic hepatitis C, and 50 healthy controls. The rate of monosomy X was assessed in peripheral white blood cells with fluorescence in-situ hybridization.

In all groups, the researchers found that the rate of monosomy X increased with age. However, the age-related rise was steeper in the primary biliary cirrhosis group than in the other groups.

After adjusting for age, the rate of monosomy X in the primary biliary cirrhosis group was nearly two times higher than that of the other groups, the investigators point out. Within the primary biliary cirrhosis group, monosomy X rates did not differ by disease stage or by serum bilirubin level.

The increased rate of monosomy X in the primary biliary cirrhosis group suggests "the presence of X chromosome instability," the authors state. "No convincing explanation has been given for female predisposition to autoimmune diseases but, based on the present data and the assumption that X chromosome defects might also exist in men with primary biliary cirrhosis, we suggest that the X chromosome could play a major part."

Lancet 2004;363:533-535.