Restless Legs Syndrome Common in X-linked Adrenoleukodystrophy

Restless legs syndrome occurred in approximately 40% of adults with X-linked adrenoleukodystrophy, based on data from 32 individuals.

Patients with X-linked adrenoleukodystrophy (ALD), a neurodegenerative disease, often experience gait and balance problems, as well as leg discomfort, sleep disturbances, and pain, wrote John W. Winkelman, MD, of Massachusetts General Hospital, Boston, and colleagues. Restless legs syndrome (RLS) has been associated with neurological conditions including Parkinson’s disease, but the prevalence of RLS in ALD patients has not been examined, they said.

In a pilot study published in Sleep Medicine, the researchers identified 21 women and 11 men with ALD who were treated at a single center. The median age of the patients was 45.9 years. Twenty-seven patients had symptoms of myelopathy, with a median age of onset of 34 years.

The researchers assessed RLS severity using questionnaires and the Hopkins Telephone Diagnostic Interview (HTDI), a validated RLS assessment tool. They also reviewed patients’ charts for data on neurological examinations, functional gait measures, and laboratory assessments. Functional gait assessments included the 25-Foot Walk test (25-FW), the Timed Up and Go test (TUG), and Six Minute Walk test (6MW).

Thirteen patients (10 women and 3 men) met criteria for RLS based on the HTDI. The median age of RLS onset was 35 years. Six RLS patients (46.2%) reported using medication to relieve symptoms, and eight RLS patients had a history of antidepressant use.

In addition, six patients with RLS reported a history of anemia or iron deficiency. Ferritin levels were available for 14 patients: 8 women with RLS and 4 women and 2 men without RLS; the mean ferritin levels were 74.0 mcg/L in RLS patients and 99.5 mcg/L in those without RLS.

Of the seven ALD patients with brain lesions, all were men, only two were diagnosed with RLS, and all seven cases were mild, the researchers noted.

Overall, patients with RLS had more neurological signs and symptoms than those without RLS; the most significant were pain and gait difficulty. However, patients with RLS also were more likely than were those without RLS to report spasticity, muscle weakness, impaired coordination, hyperreflexia, impaired sensation, and paraesthesia, as well as bladder, bowel, and erectile dysfunction.

The 40.6% prevalence of RLS in patients with ALD is notably higher than that of the general population, in which the prevalence of RLS is 5%-10%, the researchers wrote in their discussion.

“Consistent with patterns observed in the general population, risk factors for RLS in this cohort of adults with ALD included female gender, increased age, lower iron indices, and use of serotonergic antidepressants,” they said.

The study findings were limited by several factors including the small size and the possible contribution of antidepressant use to the high rate of RLS, the researchers noted.

“Awareness of RLS in patients with ALD would allow for its effective treatment, which may improve the functional impairments as well as quality of life, mood, and anxiety issues in those with ALD,” they concluded.

The study received no outside funding.

Winkelman disclosed ties with Advance Medical, Avadel, Disc Medicine, Eisai, Emalex, Idorsia, Noctrix, UpToDate, and Merck Pharmaceuticals, as well as research support from the National Institute on Drug Abuse and the Baszucki Brain Research Foundation. The study also was supported by grants from the National Institute of Neurological Disorders and Stroke, the European Leukodystrophy Association, the Arrivederci Foundation, the Leblang Foundation, and the Hammer Family Fund Journal Preproof for ALD Research and Therapies for Women.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.