What is the probability that the first son of a woman whose brother has Lesch-Nyhan syndrome will be affected?

The effect of it would be its her brother it runs in her family of the syndrome so of course there would be a most likely chance of her first son getting it because its her first son and the sysndrome is in her brother which is blood and her son which is blood. he may not get the full effect but he would get maybe the whole effect or some of the effect.