Hey Worriedsister,

Welcome.  I'm sure that you must be worried about your brother and what having MS means.  There could be other causes for the symptoms you are experiencing, but if they continue to trouble you, then certainly talk to your doctor about it.

Here's some information I had collected at one point:

The direct cause of MS is unknown and there are many theories involving viral exposure, environmental factors, and hereditary markers.  Just two years ago, the NMSS stated that the average person in the US has a 1 in 750 chance of developing MS.  If the same person has a parent with MS, the risk increases to about 1 in 40.  

I remember reading that about 5% of people with MS have a brother or sister who is affected and about 15% have a close relative who is affected.  So it does seem that heredity plays a role, but it also means that 85% of people with MS have no close relatives who are similarly affected.

There is important research ongoing which seeks to identify genes and genetic markers which help to regulate the immune system.  Just one year ago, researchers part of the International Multiple Sclerosis Genetics Consortium announced that they had uncovered new genetic variations associated with MS.

You are and your brother twins?  If so, when one twin develops MS, it does increase the risk of the other twin developing MS.  An increase - but not a certainty.

And it's completely possible that you are experiencing sympathetic symptoms, or are just noticing symptoms which you might have previously ignored, having recognized them as possibly being related to MS.  Are you experiencing any other symptoms?

Come back and let us know.  We're here to listen and provide support.  I do wish you the best.  I hope this helps.

Lisa