We have evaluated over 5000 patients over 20 years. And based on over 90 plus pct having other members of their family with a disfluency it is clear this is a genetic disorder and it seems the gene itself has been o=identified. Scientific America a few years ago finally came out with an article confirming what we have found ling ago. The neurological disorder it causes of involuntary closing of the vocal cords is what is happening why well that is still unknown.