Our son had whole exome sequencing and in doing so, they tested us, the parents as well. No variants came up for that gene, or any other gene detailed in stuttering studies. I did have a variant in the PLXNB2 gene, which does have neurological implications, so who knows. Now for my unsolicited advice.... > I love every piece of him the way he is. Tell him this. If you already have, do it a few more times. Growing up noone told me this or that it's ok to stutter. It was always, you're broken and need to be fixed. And that's the root of the anxiety...the shame that leads to the fear. If he really wants to lessen the anxiety, he needs change the stuttering mindset (dont focus on how youre going to sound, focus on the context of the situation),accept more, avoid less. If he pushes himself outside his comfort zone, anxiety will lessen. If you enable him (order for him, call for him) you may want to.discuss that with him and come up with a plan to reduce that. Psychotherapy may help (something like CBT) and I suggest him finding a stuttering support group. He could even call me if he wants lol.