Question about a genetic disorder I’m trying to find out

Patient: Hello, I have a friend who is a girl told me she is getting some injection because she might be a carrier because her mum is, and so I thought the girl’s grandparents and her other ancestors got some genetic disorder that affect males to be permanently disabled because the daughter (the girl’s mum) is fine and healthy but the genetic disorder made the girl’s uncle (her mum’s brother) permanently disabled and on a wheelchair and the mum recently gave birth to a boy so they are going to test him seeing if he got the disorder.I heard this kind of thing before but I don’t know what the name I can’t tell if it is a really rare genetic disorder or just uncommon, so hopefully I made it clear as I can and if you know what is the disorder that will be really handy. Thank you.

Doctor: