Conversely, a study including four LRRK2 R1441G PD patients in the Basque Country of Spain stated that these had a limited DBS response on motor function, daily life activities and quality of life, an inferior outcome compared to 41 LRRK2 mutation-negative DBS-treated control patients, yet not supported by statistical hypothesis testing.31 This evidence concerns the gene LRRK2 and Parkinson disease.