Whispering dysphonia (DYT4 dystonia) is caused by a mutation in the TUBB4 gene
Lohmann, Katja, Robert Wilcox, Susen Winkler, Alfredo Ramirez, Aleksandar Rakovic, Jin-Sung Park, Björn Arns, et al. 2013. “Whispering Dysphonia (DYT4 Dystonia) Is Caused by a Mutation in the TUBB4 Gene”. Ann Neurol 73 (4): 537-45.