Evaluation of the Effects of Calcitriol's in the Neurological Symptoms of Friedreich's Ataxia Patients

Friedreich's Ataxia (FA) is a recessive hereditary disease due to GAA (Guanine-Adenosine-Adenosine) triplet repeats in the FXN (Frataxin) gene. This gene codifies for the frataxin protein, the lack of which produces the neurological and cardiac symptoms. The exact mechanisms why the lack of frataxin produces the disease aren't well understood, but it is known that frataxin is located in the mitochondria. Calcitriol synthesis, a mitochondrial process, could be impaired in FA due the reduction of CYP27B1 (Cytochrome P450, family 27, subfamily B, member 1) and Fdx1. Because of some studies have shown that Calcitriol (the active form of D Vitamin) could raise the frataxin levels, it could have a beneficial effect in patients with FA. Description of the trial: to assess the effect of Calcitriol 0.25mcg/24h for a year in the neurological function of FA patients. Main objective of the trial: to evaluate the effects of Calcitriol in the neurological symptoms of patients with FA. The second objectives of the trial are: 1. To evaluate the safety and the risk of hypercalcemia with the treatment with low dosis of Calcitriol (0.25mcg of Calcitriol every 24h) in patients with FA. 2. To measure de change in the Frataxin's levels during the treatment with Calcitriol. 3. To evaluate the effects of Calcitriol in the daily life activities and the life quality of the patients with FA. Sample size: The number of participants needed to compleat the trial is 20. Duration: The duration of the trial is one year Procedure: * Before taking part in the study, it will be ensured that participants fulfill all the inclusion criteria with a detailed questionnaire. * During the clinical trial the following test will be done: 4 electrocardiogram, 5 blood analysis to control de risk of hypercalcemia and to measure the frataxin's levels, and 3 full neurological examinations. Post trial treatment details: The patients who wish to continue with the treatment will be allowed to do so, at least until the results of the comparison of the basal neurological evaluation with the second and the final neurological evaluation are obtained. If the results are positive, the treatment will be continued with regular blood tests controls. If the results don't demonstrate a statistically significant effect, the treatment will be interrupted in all patients.