Association of fibroblast growth factor (FGF-21) as a screening biomarker for chronic progressive external ophthalmoplesia

Purpose: To investigate whether or not fibroblast growth factor (FGF-21) can be used as a screening biomarker in chronic progressive external ophthalmoplesia (CPEO) patients. Methods: FGF-21 concentration was measured in the serum of 24 patients with CEPO phenotype and 24 control samples by enzyme-linked immunosorbent assay (ELISA) and determined the deletion of mitochondrial genome by multiplex polymerase chain reaction (PCR). Results: FGF-21 concentration in 50% of CPEO patients showed notable differences from that in control subjects. FGF-21 concentration ratio in patient group,2 disorder control groups (mitochondrial and non-mitochondrial) and normal group,respectively,was 294.87 ± 42.10 (p 0.0001),761.78± 75.07 (p 0.0001),124.26 ± 12.27 (p = 0.1203),69.27 ± 10.09 (p = 0.2195). A statistically significant inverse correlation between FGF-21 concentration and age onset was found,with a significant difference (p 0.05) in the age group ≤ 19 years (mean FGF-21 concentration,460.36 pg/mL) and for the age group ≥ 51years (mean concentration FGF-21,57.87 pg/mL. Surprisingly,there was no significant difference between FGF-21 concentration and age in the mid-age group (20 - 50 years). Conclusion: These findings indicate that FGF-21 concentration significantly increases in CPEO patients like in other mitochondrial disorders and this factor can be used as a biomarker in primary diagnosis of mitochondrial disorders. In this regard,FGF-21 assay is only valid in teenagers and the 50 years age group who show acute symptoms.