[Eosinophil-derived neurotoxin as a new additional clinical marker in spinal muscular atrophies].

BACKGROUND

Spinal muscular atrophies (SMA) are group of neuromuscular disorders characterized by degeneration of motorneurons in anterior column of medulla spinalis, and sometimes in motoneurons of cranial nerves and the brain. Causes of SMAs are mutations in genes encoding for SMN, SIP and NAIP that are very low in motorneurons of these patients. Ribonucleases (RNases) are enzymes that depolimerize RNA and may destabilize DNA.

OBJECTIVE

The objective of this study was to determine ribonuclease activity in serum and urine of SMA patients.

METHODS

RNases were purified by anion-kation-exchange chromatographies, and HPLC, and their activity was measured by immunodetection using specific antibodies against rinonucleases in presence of RNA as a substrate.

RESULTS

Eosinophil-derived neurotoxin (EDN) activity iin serum of SMA patients was 5.6, 3.8 and 2.6 higher in type I, II and III comparing with control group. RNase inhibitor activity in serum of the same patients was 3.0 and 2.4 lower in type I and II vs. Control group, but in type III was unchanged. Similar results are found in urine of the same patients.

CONCLUSIONS

Increased serum and urin EDN activities in SMA patients could be used as a new additional clinical marker in their diagnosis.