What causes the Marshall-Smith Syndrome?

MSS is a congenital condition. It is caused by a change (mutation) in the genetic material. The gene where the change that causes MSS was found, is called NFIX.

There is nothing you can do or not do to prevent a child from being born with this condition.

The condition is not hereditary. In this case doctors call it a ‘spontaneous mutation’. So parents of a child with MSS don’t need to be tested for the syndrome. There is no increased risk of giving birth to another child with MSS when you already have a child with the syndrome.