Men More Likely to Pass MS to Their Children

Men may be 2.2 times more likely than women to transmit multiple sclerosis (MS) to their children, according to a study by Orhun Kantarci, MD, assistant professor of neurology at the Mayo Clinic College of Medicine, Rochester, Minnesota, and colleagues. The overtransmission of the disease by fathers may indicate that nontraditional, epigenetic factors play a role in the transmission of MS.

The study authors reviewed the records of 197 families in which the father or mother had MS. Researchers collected these data from the Mayo Clinic, the University of California at San Francisco, the University of California at Berkeley, and Kaiser Permanente in Oakland, California. Of the total population of 441 children, 45 had MS. Eighteen fathers with MS transmitted the disease to their children; 99 did not. Twenty mothers with MS transmitted the disease to their children; 296 did not. These findings were independent of the sex of the affected children and irrespective of ethnicity.

Since women are twice as likely as men to have MS, Kantarci's study suggests that women may possess more environmental susceptibility, while men have greater genetic susceptibility for the disease.

"Because men have a greater physiologic resistance to MS, they must have stronger genes or a larger number of genes with which to develop MS," he said. "Therefore, these men may have a greater genetic load and transmit these genes more often to their children."This phenomenon is known as the Carter effect, whereby a disease is more commonly passed down to offspring by the parent of the sex less affected by the disease.

The citation for this study is Kantarci OH, Barcellos LF, Atkinson EJ, et al. Men transmit MS more often to their children vs women: the Carter effect. Neurology. 2006;67:305-310.