MS and Genetics

After taking a fresh look at the data from two previous genome-wide scans for MS-related gene variations, the International MS Genetics Consortium (IMSGC) concluded that MS risk is governed by a cumulative effect of dozens of allelic variants throughout the genome, probably involving as many as 100 genes (N Engl J Med. 2007; 357(9):851-862; N Engl J Med. 2010; Apr 9;86(4):621-5. To see the full collection of published genome-wide MS studies, go to www.msgene.org.

The role of genetics in MS

As the role of genetics in MS continues to be explored, the following statements can be used to help frame conversations with patients about MS risk (Compston & Coles, 2008):

• The risk of developing MS in the general population is approximately 0.1%.
• The risk for a child with one parent who has MS is approximately 2%.
• The risk for a child with two parents who have MS is approximately 12.2% (Ebers et al, 2000).
• The risk for a dizygotic twin and other siblings is approximately 5%.
• The risk for monozygotic twins is approximately 25% (Willer et al, 2003).
• The risk for second-degree and third-degree relatives is approximately 1%.

Conversations about the genetic contribution to MS risk should include mention of the complex interaction with environmental factors that appears to exist.