Taurine and Friedreich’s Ataxia: An Update

Abstract

Friedreich’s ataxia is a recessively inherited spino-cerebellar ataxia appearing in childhood and relentlessly progressing to invalidity or death in middle age at the latest. A number of signs and symptoms have been found to be present in 100% of patients and are obligatory for a diagnosis, while other signs are definitely of a progressive nature (19). Incoordination of limbs (ataxia) is linked to evidence of damage to the posterior columns of the spinal cord and of dorsal root ganglia (loss of vibration and position sense), and of the pyramidal tract (absence of knee and ankle jerks, trophic changes). Most of these symptoms first appear in the lower limbs. Also observed are skeletal deformities (pes cavus, kyphoscoliosis). Electrically, almost all cases of the typical disease have absent or considerably diminished sensory action potentials in the sural nerves, while motor conduction velocities are either normal or only slightly decreased. Retinitis pigmentosa is not usually seen in typical Friedreich’s ataxia, but it is often present in association with a variety of other forms of hereditary ataxia. A final feature of Friedreich’s ataxia that must be stressed is the constant presence of a cardiomyopathy as evidenced by abnormal echocardiograms, vectocardiograms or electrocardiograms, singly or in combination. This cardiomyopathy is usually hypertrophic in type and occasionally obstructive; it appears to be an integral part of Friedreich’s ataxia, and not a phenomenon secondary to the disease process. The most important histological changes are myocardial fibrosis and foci of degeneration of the cardiac muscle cells. Granular deposits of calcium or iron salts can occasionally be found in these muscle cells.