Outcome of bilateral deep brain subthalamic stimulation in patients carrying the R1441G mutation in the LRRK2 dardarin gene.

OBJECTIVE: Deep brain subthalamic stimulation provides symptomatic relief to patients with Parkinson's disease. The present study analyzes the postoperative outcome of deep brain subthalamic stimulation in patients carrying the R1441G mutation in the leucine-rich repeat kinase-2 (LRRK2) (dardarin) gene.

METHODS: Five of the 48 patients treated in our unit carried a mutation in the LRRK2 (dardarin) gene. All five met the Core Assessment Program for Surgical Interventional Therapies criteria for inclusion in the surgical program. Pre- and postoperative assessment (6 mo) was made using the Unified Parkinson Disease Rating Scale II, Unified Parkinson Disease Rating Scale III, and Parkinson's Disease Questionnaire-39 scores, as well as the type and dosage of drugs used.

RESULTS: The response to L-dopa after 6 months was similar to the baseline in all four patients. One suffered a stroke four months after surgery and is not eligible for evaluation. The improvements in motor response, daily life activities, and quality of life were limited (18, 22, and 33%, respectively) and were lower than those of the control group (39, 45, and 41%, respectively).

DISCUSSION: Carriers of the R1441G mutation were clinically analogous to the rest of similarly operated patients with idiopathic Parkinson's disease. However, the response to deep brain subthalamic stimulation was worse among the former. The explanation for this negative result is unclear because all patients maintained an excellent response to L-dopa. Further larger studies are needed to confirm these findings.