Saturday, July 7, 2007
Recently a phenomenon known as the Carter effect has been put in to doubt. At least for the horrible disease Multiple Sclerosis (MS).
A study published in the journal Neurology last week indicated that the transmission of MS risk is not skewed based on sex.
"Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. The precise nature of these factors and mode of inheritance remains unknown. A female predominance is universally found. Recently, offspring of affected fathers were reported to be more likely to have MS than those of affected mothers. This was attributed to the Carter effect, which is seen in polygenic disorders. The Carter effect predicts that affected parents of the sex lesser affected by a disease/trait are more genetically loaded for risk alleles and thus transmit these more often to their offspring."
The study found that both men AND women afflicted with MS transmitted the disease about 10% of the time to their offspring.
The Sherpa Says: This is a study which calls into question old notions of thinking regarding genetic predisposition. Unless this is a sex linked disease, we should not see skewing. This old thinking was much along the lines of "Only women pass on breast cancer". I am glad to see it go. However the critics of this study will note that 3 times as many afflicted mothers were studied. Also no genome wide association studies have identified any genes in this likely multifactorial disease. Patience......they will come.