Abstract Details

Title PYGM mRNA Expression In Patients With McArdle Disease: Demographic, Clinical, Genetic And Morphological Correlations.

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P5 - Poster Session 5 (5:30 PM-6:30 PM)

Poster/Presentation
Number 12-019

Objective To correlate demographic, clinical, morphological and genetic aspects from McArdle’s patients with PYMG mRNA expression in patients with McArdle disease.

Background McArdle disease is the most common glycogen storage disease in skeletal muscle, characterized by mutation in the glycogen phosphorylase gene (PYGM), with a significant clinical and genetic heterogeneity. However, previous studies could not correlate genotype and phenotype. So, what determine the severity of this disorder remains to be clarified. As far as we know, the PYGM mRNA expression and its correlation with different aspects of the disease have not been studied previously.

Design/Methods We selected 15 patients with confirmed previous McArdle’s diagnosis in order to test PYMG mRNA expression using RT-qPCR in a thermal cycler. The specific primers for the PYGMgene amplification were created using the Primer3 Input 0.4.0 software, available in http://frodo.wi.mit.edu/primer3/. The PYGM expression values were correlated with demographic, clinical, morphological and genetic parameters. To determine the cut off value to define hypoexpressed and normoexpressed genes we used ROC curve.

Results Our data did not show significant difference when PYGM mRNA expression was compared to demographic, clinical, morphological and genetic data. The area under the ROC curve presented a value of 0.7792 (95% CI = 0.6050 to 0.9533; p = 0.008) for PYGM, with a cutoff value of 2 ^- ΔCt <0.2195: sensitivity 53.33% ; specificity 93.75% . 8 samples showed PYGM gene hypoexpressed and 7 were normoexpressed based on this data.

Conclusions

The statistical analysis showed that all parameters above analyzed have no correlation with PYGM mRNA expression. Also, the gene expression demonstrated to be diminished only in 53.3 % of patients what means that the gene expression is not the only point responsible for phenotypic variability. The severity of the disease may be associated to post-transcriptional events (epigenetics). Also, the phenotype could be related to the amount of protein or its functionality.

Authors/Disclosures
PRESENTER	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
	No disclosure on file
Alzira A. Carvalho, MD (FMABC)	No disclosure on file

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