Tetrabenazine was the most effective drug in the baseline management of the severe involuntary movements in patients 1 and 7; its positive effect was previously described in 6 patients8 treated in association with neuroleptics (risperidone and haloperidol). In addition, a recently reported patient harboring the c.626G>A (p.Arg209His) exhibited an initial significant improvement with tetrabenazine and subsequent response to trihexyphenidyl.28 Emergency DBS, during a severe prolonged exacerbation, was life saving in patient 7. Three patients with GNAO1 mutations had previously been reported whose hyperkinetic exacerbations, usually preceded by illness, clearly improved after DBS insertion into the globus pallidus.7,27 Our report provides further evidence that DBS should be promptly considered in all the patients with sustained intractable movement disorder due to GNAO1 mutations.
