Jul 27, 2006
Transmitting MS To Children: Possible Differences In Men And Women
A new study shows that, in a group of 441 children with a parent with multiple sclerosis, fathers with MS were more likely to pass on the disease to children than mothers with MS. Orhun H. Kantarci, MD, Brian G. Weinshenker, MD (Mayo Clinic, Rochester, MN) and colleagues report their findings in the July 25 issue of Neurology (2006;67:305-310). The study was funded by the National MS Society, the National Institutes of Health and the Mayo Foundation.
Although MS is not directly hereditary, a person who has a first-degree relative (such as a parent or sibling) with MS has a greater risk of developing MS than a person with no MS in the family. Researchers believe that MS occurs in individuals who have genes that make them susceptible to an unknown environmental trigger or triggers. In addition, women are twice as likely as men to develop MS. The reason for this difference is unknown. Dr. Kantarci’s group examined the possibility that if men are more resistant to MS, then those men who actually develop the disease must have more susceptibility genes in order to overcome that resistance. Therefore they might be expected to pass on a larger number or stronger susceptibility genes to their children.
To investigate this idea, Dr. Kantarci’s team collected information on 3598 people from multiplex families with MS (those with more than one person with the disease) from the MS DNA Bank at UCSF, which is established and maintained with funding from the National MS Society. They studied 441 children who had a father or mother with MS, 45 of whom had definite MS. Fathers with MS transmitted the disease to 18 children, and did not transmit it to 99 children. Mothers with MS transmitted it to 27 children, and did not transmit it to 296 children. Therefore, in this study men were more than twice as likely to transmit MS to their children than women.
While the average person in the United States has about 1 chance in 750 of developing MS, the risk for a person who has a parent with MS increases to about 1 in 40. Thus, the risk increases significantly for a person whose parent has MS, but still remains relatively low.
According to the National MS Society’s Chief Medical Officer Dr. Aaron Miller, “These findings, if confirmed, are of interest to scientists searching for MS genes, but do not alter genetic counseling advice for families with a parent who has MS.”
The National MS Society is funding several large-scale studies searching for genes that make people susceptible to developing MS. Success in this area would give scientists a roadmap to the cause of MS, as well as to concrete targets for new therapies and possibly even ways to prevent the disease.