Objective: To highlight that the new clinical entity called "negative dystonia of the palate" recently described is probably more a new clinical presentation of a mutation in the THAP1 (DYT6) gene.

Background: A recent study (Sinclair et al, 2015) described a new clinical entity called "negative dystonia of the palate" in 5 patients without genetic analysis. Characteristics findings were task-specific absent palatal movement with speech, despite normal movement on swallowing, coughing and an intact gag reflex.

Methods: A 42 years old caucasian man with history of ankylosing spondylitis presents since the age of 35 years old with an hypernasal and shrill voice, initially fluctuating and then permanently. There are no problems in swallowing, there are no regurgitation and he has never taken any medication, including neuroleptics. He reports the same disease in his mother and his maternal grandfather. Because of the initial fluctuating symptoms, a congenital myasthenia had been evoked but electromyogram was normal and the test to acetylcholinesterase inhibitor ineffective. Clinically, there are also a writer’s cramp on the right upper limb and a left dystonic posture during the practice of drum. In nasofibroscopia, is observed an hypotonic palate and a dystonia (or compensation) of the tongue which is on retraction and elevation during phonation. There is no velar insufficiency because swallowing is normal (eliminating paralysis). Laryngeal elevation during phonation is responsible for the shrill voice of the patient. There is no atrophy or fasciculation of the tongue.

Results: Concerning our patient, genetic research in the THAP1(DYT6) gene found a positive heterozygous mutation. Impairment of phonation is a characteristic of patients with mutation in the THAP1 (DYT6) gene; the most frequent mutation after DYT1, with autosomal dominant inheritance, and initially affecting the craniocervical muscles before a possible generalization.

Conclusions: Any persistant dysphonia should lead to a search for an oropharyngeal dystonia (positive or negative) but also in any other part of the body. In case of primary dystonia, a search for the mutation in the THAP1 (DYT6) gene must be proposed including in front of this new clinical entity.

« Back to 2016 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/negative-dystonia-of-the-palate-mutation-in-the-thap1-dyt6-gene-found-in-a-42-years-old-patient/