Mutations in the TUBB4A gene have been identified so far in two neurodegenerative disorders with extremely different clinical features and course: whispering dysphonia, also known as dystonia type 4 (DYT4), and hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC).
Consistent with H-ABC's clinical presentation, TUBB4A is highly expressed in neurons, and a recent report has shown that an N-terminal alteration is associated with a heritable dystonia.