Docosahexaenoic Acid (DHA) Replacement for Treatment in Spinocerebellar Ataxia 38

Overview

The project will study a therapeutic approach in Spinocerebellar Ataxia (SCA38) by DHA replacement. SCA38 is caused by missense mutations in the ELOVL5 (Elongation of very long chain fatty acids protein 5) gene. Background/Rationale: ELOVL5 is a microsomal fatty acid elongase gene required for the synthesis of arachidonic acid and DHA. In brain, it shows a peculiar high expression in cerebellar Purkinje cells. The ELOVL5 products, such as DHA, are decreased in SCA38 patients serum and DHA administered as a dietary supplement has been shown to improve SARA scores, to ameliorate quality of life, and to increase brain cerebellar hypometabolism (FDG-PET) in two SCA38 patients. Experimental Plan: The investigators will perform a randomized placebo-controlled trial by DHA supplementation on ten SCA38 patients, followed by an open-label phase. Expected results: DHA supplementation should be able to improve symptoms in SCA38 and to improve cerebellar hypometabolism in these patients.

Spinocerebellar ataxias (SCAs) include over thirty different subtypes of central nervous system diseases that affect approximately 1 in 30,000 persons. The investigators have identified the causative gene for SCA38, a novel rare form of cerebellar ataxia. Estimated frequency of the disease is below 1% of SCAs. The disease gene encodes an enzyme involved in omega-3 fatty acid biosynthesis, whose products are reduced in SCA38 patients' serum. The investigators reasoned that the administration of specific omega-3 fatty acids could ameliorate the disease symptoms in SCA38 patients. Indeed, preliminary data obtained in a pilot trial on two patients, now in their 8th-month therapy, are remarkable, with an improvement of disease symptoms and quality of life, without any adverse effect. The investigators will perform a clinical trial to prove this therapeutic strategy of SCA38. The investigators will evaluate clinical SARA scores, ICARS scores, brain PET images, and plasma metabolic pattern in ten SCA38 patients. The trial will consist of two phases: 1) a randomized double-blind placebo/treatment (600 mg DHA/day) from T0 (baseline observation) to T1 (evaluation at four-month). Patients who will meet the study eligibility criteria will be randomized to receive the drug or the placebo (ratio 1:1). A second open-label phase on all patients from T2 (6 months) to T5 (30 months) will be performed with repeated measures of the medication group (n=10). Patients will complete a personal diary during the whole treatment and a quality of life questionnaire at each visit. The primary outcome will be the clinical improvement, whilst secondary outcome will be considered the improvement of brain metabolism by PET-FDG. At each time point, clinical evaluation (video-record of SARA/ICARS scores) will be performed. Videos will be randomized and evaluated blindly by two independently clinicians. At T0, T1, T2, T5, patients will undergo brain PET-FDG scan. PET-FDG scans will be performed by the same scanner at the University of Brescia. This project will provide helpful data on possible replacement treatment in this novel form of cerebellar degeneration.