The results, based on brain MRIs of 759 consecutive MS patients, support the hypothesis that a patient's genetic make-up plays a role not only in development but also in severity of the disease.
A University at Buffalo team of neurologists and imaging experts headed by Robert Zivadinov, M.D., Ph.D., professor of neurology, conducted the research at the Buffalo Neuroimaging Analysis Centre (BNAC).
"From the early 1980s on," said Zivadinov, "MS researchers thought that genetic factors likely played a role in the disease, that its traits were determined by several different genes, and our findings support this hypothesis.
"Our MRI analysis showed a difference between the severity of disease characteristics in familial MS patients versus what we call sporadic, or non-familial, MS patients," he said. "These differences may be related to some disease-modifying genes, but to prove this, we must do further investigation."
MS destroys myelin, the fatty sheath that protects nerve fibres carrying message traffic from various muscles to and from the central nervous system. For reasons currently unknown, in some people the myelin sheath breaks down, resulting in destruction of the nerve fibres and the symptoms of MS.
This demyelization process leads to mild to serious disability, from slight numbness of the limbs to loss of vision and paralysis.
Of the 759 patients, 478 had relapsing-remitting MS, involving acute attacks with full or partial recovery; 222 had secondary-progressive MS, characterised by occasional attacks and sustained progression; 30 had primary-progressive MS with steady worsening from onset, and 29 had experienced their first attack.
Analysis showed that compared to patients with no family history of MS, familial MS patients had significantly more destructed lesions, and significantly lower volume of whole brain, white matter and grey matter, as well as other indications of greater brain degradation.
"Patients whose parents, children or siblings had MS showed more damage than patients who had cousins with MS," Zivadinov said. "This indicates that the closer the relationship, the greater the risk of MS.
"Of particular interest is the finding of more severe grey matter damage and more lesions, particularly in those with MS in first-degree relatives. These findings are very interesting and we will be investigating them further." – (EurekAlert!)