[Spinocerebellar ataxia type 2 in Cuba. A study of the electrophysiological phenotype and its correlation with clinical and molecular variables].
BACKGROUND
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 exon of disease causing gene, and it is characterized by a high variability in its clinical and electrophysiological presentation, even intrafamiliarly.


OBJECTIVE
Factors identification, which explains this variability, could lead to the findings of therapeutical ways that may retard the disease onset.


METHODS
We have done this research in order to contribute to this phenotypic variability knowledge of the different structures and functions of the nervous system.


RESULTS
By means of molecular and electrophysiological studies we have found two groups well differentiated in a 52-patient sample. The first one was characterized by CAG repeat expansions above 41 units and by the total blockade of the afferent conduction that is, basic electrophysiological alteration with axonal damage predominance. The second one was characterized by CAG repeat expansions lower or equal to 41 units and showed a high variability in it s electrophysiological behavior with myelinic damage predominance. We realized of the existence of statistical significance correlations between the electrophysiological, clinical and molecular variables considered.


CONCLUSIONS
These findings suggest that for by CAG repeat expansions lower or equal to 41 units should be affecting other genetics and/or environmental factors that explain the variability found in this group which are not significant for clinical and electrophysiological presentation in individuals with CAG repeat expansions above 41 units.
Velázquez Pérez
L
L
Servicio de Neurofisiología Clínica; Hospital Docente Provincial Vladimir Ilich Lenin, Holguín, Cuba. ataxia@cristal.hlg.sld.cu
Almaguer Mederos
L
L
Santos Falcón
N
N
Hechavarría
R
R
Sánchez Cruz
G
G
Paneque
H M
HM
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003462:Cuba; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D010802:Phylogeny; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000145:classification / Q000235:genetics / Q000503:physiopathology*; D013223:Statistics as Topic; D019680:Trinucleotide Repeat Expansion / Q000235:genetics*
Ataxia espinocerebelosa tipo 2 en cuba. Estudio del fenotipo electrofisiológico y su correlación con variables clínicas y moleculares.