Scientists believe they have discovered the reason why multiple sclerosis affects more women than men.
A new study has shown women with MS are more likely to carry a gene linked to the illness than men who have the condition.
Although the causes of MS remain a mystery, scientists have long suspected that patients carry a genetic susceptibility and that something in their environment then triggers the condition.
The study – which was carried out on more than 7000 people – showed that women are also more likely to pass the mutation to their daughters than their sons, and more likely to share the MS-susceptibility gene with more distant female family members.
People with MS, who had a specific gene variant known to increase the risk of developing the condition, were around three times more likely to be women than men.
The research also revealed that the number of Scots diagnosed with MS has been rising, and the rate has been increasing faster among women than for men.
BBC journalist Elizabeth Quigley, who is married to Finance Minister John Swinney, is among those living with the condition. She has publicly described living with the condition as “tough at times”. Scotland currently has the highest prevalence of multiple sclerosis in the world, with around 10,500 people living with the condition.
Led by Professor George Ebers, a team of researchers from the University of Oxford, examined the genes in 1055 families, in which at least one person had MS.
In total, the genes of 7093 people were tested, including 2127 people with MS. A full 73% of those patients were female.
The researchers discovered that women with MS were 1.4 times more likely to have the Human Leukocyte Antigen (HLA) gene variant associated with MS, than men with disease.
A total of 919 women and 302 men had the HLA gene variant, compared to 626 women and 280 men who did not have the gene variant.
The research paper said: “There is general consensus that the incidence and prevalence of MS has been rising with an increased penetration among women. Moreover, there is a maternal parent-of-origin effect with higher number of affected mother-daughter pairs and few father-son pairs.”
But the scientists added the increase in MS among women had happened in “too short a time period” to suggest it was caused simply by genetic factors.
Mr Ebers, of the University of Oxford, said: “The idea that the environment would change genes was once thought to be ridiculous.
“Now it is looking like this is a much bigger influence on disease than we ever imagined. Our findings also show women with the HLA gene variant are more likely to transmit the gene variant to other women in their families than to men,”
MS is an autoimmune condition and the most common disabling neurological disease among young adults. There are three main types of MS – primary progressive, secondary progressive and relapsing remitting, in which symptoms diminish before reappearing.
The exact cause is not fully understood, but there is evidence to suggest it is brought about by a combination of genetics and environmental factors. The new study also shows that an individuals’ risk of carrying the gene variant, and going on to develop MS, was higher if a second degree relative also carried that gene variant and had MS, rather than if a parent did.
Of the 10,000 Scots living with MS, around 6500 of them are women, according to the MS Society.
In the 1950s, the number of men and women living with MS in Scotland was roughly equal.
However, today MS may affect as many as three times more women in the country than men.
The research also offers an explanation as to why certain people are affected, as around 20% of MS patients have at least one affected relative.
The paper’s authors said the ratio of women to men MS sufferers has gone up to 3:1 in Scotland.
In September, Harry Potter creator JK Rowling – whose mother died from MS aged 45 – gave £10 million to set up an MS research clinic in Scotland.
The Edinburgh University-based centre will focus on patient-based studies to find treatments that could slow progression of the condition and eventually stop and reverse the disease.
BBC journalist and MS sufferer Elizabeth Quigley has also spoken publicly about living with the disease.
Ms Quigley, who is married to Finance Minister John Swinney, said the condition was “tough at times” but that she was “just another Scot living with MS”.
Director of policy and research at the MS Society, Dr Jayne Spink, said: “The exact cause of MS is still unknown, but this study helps solve a vital part of the puzzle which we hope will lead to ways to reduce the risk of developing MS in future generations.”
Tuesday, January 11, 2011
From The Herald in Scotland:
Posted by BA Haller at 9:29 PM