Ataxia espinocerebelosa tipo 2 en Cuba: estudio del fenotipo electrofisiológico y su correlacióncon variables clínicas y moleculares / Spinocerebelar ataxia Type 2 in Cuba: a study of the electrophysicological phenotype

ABSTRACT

The spinocerebellar ataxia type 2 has a prevalence of 43 per 100,000 inhabitants in Holguín province,which is the highest one reported worldwide. It is due to an intergenerational CAG repeat expansion contained in the first exonof diseasecausinggene, and it is characterized by a high variability in its clinical and electrophysiological presentation, evenintrafamiliarly. Objective. Factors identification, which explains this variability, could lead to the findings of therapeuticalways that may retard the disease onset. Patients and methods. We have done this research in order to contribute to thisphenotypic variability knowledge of the different structures and functions of the nervous system. Results. By means of molecularand electrophysiological studies we have found two groups well differentiated in a 52patientsample. The first one wascharacterized by CAG repeat expansions above 41 units and by the total blockade of the afferent conduction that is, basicelectrophysiological alteration with axonal damage predominance. The second one was characterized by CAG repeat expansionslower or equal to 41 units and showed a high variability in its electrophysiological behavior with myelinic damage predominance.We realized of the existence of statistical significance correlations between the electrophysiological, clinical and molecularvariables considered. Conclusions. These findings suggest that for by CAG repeat expansions lower or equal to 41 unitsshould be affecting other genetics and/or environmental factors that explain the variability found in this group which arenot significant for clinical and electrophysiological presentation in individuals with CAG repeat expansions...(AU)