Selective Mutism

Does anyone on here have Selective Mutism? My son has struggled with Selective Mutism (in educational settings) for about 16 years and it’s just struck me that we’ve never had a conversation with another person who has Selective Mutism. I’m new(ish) to this community so I just thought I’d ask if anyone else has gone through their whole education with Selective Mutism. And also if you have managed to overcome it - how did you do that? 
We’re basically just interested in hearing about other people’s experience of this. Thanks Sunflower