IQUIFIB   02644
INSTITUTO DE QUIMICA Y FISICOQUIMICA BIOLOGICAS "PROF. ALEJANDRO C. PALADINI"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A Novel Assay for Protein Analysis in Friedreich?s Ataxia (FRDA): Implications for Diagnosis and Clinical Trial Design.
Autor/es:
GABRIELA BEATRIZ RAINA; CLAUDIA PERANDONES; CALVO DS; RADRIZZANI MARTIN; GIUNTINI DE JUAREZ ME; FARAH S; RALPH PICKIELMI; MICHELI FE; FERRARI A; SANTOS J
Lugar:
Philadelphia
Reunión:
Congreso; 66th American Academy of Neurology Meeting; 2014
Institución organizadora:
American Academy of Neurology
Resumen:
OBJECTIVE: To develop a new assay to improve frataxin measurement as a second diagnostic step for patients with suspected FRDA. BACKGROUND: FRDA is the most common hereditary ataxia in Caucasians. The molecular defect in FRDA involves GAA trinucleotide expansion in the first intron of the frataxin-encoding gene (FXN). To date, only four studies have tried to quantify frataxin levels in FRDA carriers, controls and patients. DESIGN/METHODS: Patients. Twelve patients with classic FRDA phenotype (10 homozygous for GAA expansion and 2 harboring GAA expansion in compound heterozygosis with FXN point mutations carriers), and 10 healthy controls were enrolled. FXN determination. Frataxin was measured using an in-house competitive enzyme immunoassay. In contrast to other FXN measurement tests, the assay developed in our laboratory depends on a single specific sera (from rabbits), with no need of additional capture antibodies, thus resulting in a high-sensitivity and low-cost determination. Data analysis. FXN levels were determined interpolating each sample in a four-parameter standard curve, using Graph Pad Prism software. FXN levels were then normalized by total protein content, and expressed as fg of FXN/μg total protein. RESULTS: High levels of FXN (3.4?0.9 pg/mg of total protein) were found in controls, whereas FRDA patients had significantly lower levels (0.1?0.2 pg/mg). It is noteworthy that our data support whole blood as the source for FXN measurement. CONCLUSIONS: We developed a novel high-sensitivity assay for FXN measurement which allowed us to differentiate FRDA patients and healthy individuals.We are proposing this method for its use as an attractive biomarker for clinical trials and also prior to full FXN sequencing if genetic testing reveals heterozygous expansion, family history is non-informative, and/or clinical symptoms are not fully evident.