Deep Brain Stimulation In Patients With Primary Dystonia With GNAL Mutation: A Case Series (P7.066)

OBJECTIVE: We describe three cases of primary dystonia with GNAL mutation after DBS. BACKGROUND: GPi DBS, widely used to treat generalized dystonia, may be considered for focal and segmental cervical dystonia. A gene-dependent response to DBS is seen in DYT-1 dystonia but response is mixed in the limited number of DYT-6 cases. To further understand genotype response to DBS, we report the first cases of GNAL mutation dystonia with DBS. DESIGN/METHODS: We reviewed best available medical records and subjective reports of patients, participating in dystonia genetic studies, with GNAL mutations and GPi DBS. RESULTS: Three subjects with truncating GNAL mutations (2 frameshift, 1 nonsensense) had GPi DBS after insufficient response to cervical chemodenervation and oral medications. Subject one’s initial neck and voice symptoms at age 23 progressed to a 90 degree neck tilt and left hand spasm. Surgery at age 41 significantly improved her neck tilt to 15 degrees, but her voice and left arm dystonia worsened at age 44. Patient 2 is a 56 year old woman who, at age 37, had neck tremor and pain, which progressed to severe laterocollis, bilateral shoulder elevation, and left arm tremor. Her cervical dystonia had at least 80 percent improvement after surgery at age 53. Patient 3 is a 56 year old man, whose cervical dystonia began at age 44, and presented with severe laterocollis. Surgery at age 53 caused moderate but sustained improvement in his cervical dystonia. All had significant pain, with improvement after surgery. CONCLUSIONS: This case series suggests amelioration of severe cervical dystonia symptoms after DBS in GNAL mutation carriers. However, the response was not sustained in 1:3 and was incomplete in another. Therefore, further study is warranted to understand optimal lead placement, stimulation parameters, and surgical candidacy.