Is MS hereditary?

Yes..but low .. Even in identical twins, the incidence is only 20-35%, thus environmental factors (infections such as epstein virus, geography, vitamin d deficiency? +others factors, unknown) play more important role than genetic in development of ms..There is still much ongoing research in this area and hopefully will shed more light in the years ahead. It is a difficult one if you have ms, best of luck to you.
Susceptibility. We do know that there are susceptibility genes, and there can be increased risks in identical twins, mothers passing to their children, etc. But the risks are relatively on the low side, and the genetics mainly reflect a tendency to get ms if certain environmental events subsequently occur. However genetics plays a role, we feel the disease is autoimmune, not hereditary.