How do you prevent X-linked spinal bulbar muscular atrophy?

Answer 1

The only way is to prevent the birth of an affected boy. You can do a test on an already conceived fetus (amniocentesis or chorionic villous sampling) or you can have in vitro fertilization and test the eggs prior to implantation.

In all x-linked diseases only boys are affected because they only have one x-chromosome whereas girls have two. An affected male gives his x-chromosome to his daughters (whether the man gives the x- or the y determines gender) and they are unaffected due to the "good" x from the mother. Half the daughters of these carriers will be carriers themselves and half of the sons will be affected depending on which x is passed down.

One the baby is born there is no way to prevent it (yet).