Circulating nucleic acids (CNA) are present in small amounts in the plasma of healthy individuals. However, increased levels of plasma CNA have been reported in a number of clinical disorders like cancer, stroke, trauma, myocardial infarction, autoimmune disorders, and pregnancy-associated complications. CNA has received special attention because of its potential application as a non-invasive, rapid and sensitive tool for molecular diagnosis and monitoring of acute pathologies and the prenatal diagnosis of fetal genetic diseases. This review throws light on the current status of blood CNA as a diagnostic marker and its potential as a powerful tool in the future.

DNA triplet repeat expansion-associated ataxias, Friedreich's ataxia, and different types of spinocerebellar ataxias (SCAs) are progressive multisystem neurodegenerative disorders. The diagnosis of this wide group of inherited ataxias is essentially based on clinical findings. Cell-free circulating DNA in plasma has been considered as a powerful tool in clinical diagnosis and prognosis of several human diseases. In the present study, clinically suspected patients were assessed on the International Co-operative Ataxia Rating Scale and further confirmed by molecular analysis of DNA triplet repeats. Quantification of plasma DNA using a highly sensitive and DNA-specific PicoGreen fluorescent assay was done. We found significantly high levels (p < 0.001) of plasma DNA of 167 ± 43 ng/mL in Friedreich's ataxia patients (n = 15), 148 ± 29 ng/mL in SCA2 patients (n = 10), and 137 ± 29 ng/mL in SCA12 patients (n = 25), whereas those of healthy controls (n = 20) was only 59 ± 15 ng/mL. Therefore, we were able to distinguish between ataxia patients and healthy controls using plasma DNA. Although the precise mechanism by which plasma DNA enters into circulation is not known, significantly higher concentrations of plasma DNA appears to be due to neuronal and muscular degeneration in these patients. Identification of genes in plasma DNA, which are overexpressed or novel, can be a promising tool for the prognosis of these diseases.

No abstract

No abstract

No abstract