Friedreich's ataxia (FRDA) is an autosomal recessive disorder caused by the intronic (GAA ) repeat expansion in the FXN gene on chromosome 9q13. The expanded repeats acts as a transcriptional inhibitor, decreasing the expression of the protein frataxin, which leads to progressive cardio- and neurodegeneration.

Clinically suspected FRDA patients (n = 65) were assessed on the Friedreich's Ataxia Rating Scale (FARS), and genetic confirmation was done by analyzing (GAA) expanded repeats via long range PCR. Twenty patients were confirmed for FRDA, with FARS scores of 80 ± 6. PBMC proteomics of homozygous FRDA patients and age- and gender-matched healthy controls was done using two-dimensional difference in-gel electrophoresis and differentially expressed protein spots were selected ((fold change ≥1.5; P < 0.05) and identified by LC-MS/MS.

Quantitative proteomic analysis revealed 11 differentially expressed protein spots. These proteins were found to be associated with various pathophysiological aspects of FRDA such as neuropathy and neurodegeneration (Chloride intracellular channel protein 3; Interferon inducible protein AIM2; GTPase activating Rap/Ran GAP domain like protein3; T complex protein 1), ataxia (apolipoprotein A-I;Annexin 1), oxidative stress (Caspase8), Hypertrophic cardiomyopathy (Ca/Calmodulin dependent protein kinase ; Actin α cardiac muscle 1; β-enolase ), Diabetes (Mitogen activated protein kinase kinase), Muscle spacity (T complex protein 1).