To report a case of abetalipoproteinemia presenting with severe tremor and ataxia, and treated with bilateral thalamic deep brain stimulation (DBS) with over 10 years of follow up.

Abetalipoproteinemia (ABL) is a rare metabolic disorder inherited in an autosomal recessive pattern, due to homozygous or compound heterozygous mutations in the MTTP gene. This results in lipid and fat-soluble vitamin deficiencies. Neurologic symptoms include ataxia, tremor, and hyporeflexia (with associated reduced vibratory sense and proprioception). Our patient is the first reported to undergo DBS for ABL (Mammis, et al. 2012). With a decade of follow up, we can endorse the potential for long lasting benefit of DBS for this condition.

Our subject was diagnosed with abetalipoproteinemia at age 17 after two years of progressive ataxia and axial and bilateral arm tremors. Laboratory studies revealed low cholesterol and Vitamin E levels. Genetic analysis showed a homozygous MTTP mutation (c.2593 G>T). Vitamin supplementation stabilized his tremor and ataxia. His high-amplitude action and postural tremor continued to be functionally impairing. The tremor was refractory to gabapentin, propranolol, clonazepam, primidone, and sodium oxybate and at age 41, he underwent staged bilateral deep brain stimulation (DBS) of the ventral intermediate (VIM) thalamus.

Postoperatively he had significant tremor improvement. His gait worsened immediately post-surgery, but then stabilized and slightly improved compared to baseline. Eleven years later, he has had a significant sustained tremor response. The beneficial response in ataxia has also been maintained over time. The stimulation required for effective tremor control has increased slowly over time. Multipolar stimulation with high pulse and amplitude was used to effectively maintain tremor control.

VIM DBS is an effective and durable treatment for axial and appendicular tremor and ataxia in this rare movement disorder.