New laboratory indicators of polysystemic mitochondrial failure in children

It is known that biopsy and DNA sequencing methods are used to diagnose mitochondrial diseases, but such diagnostic options are not available for all tissues, especially for the central nervous system. This article analyzes the effectiveness of biomarkers — FGF-21 and GDF-15, lactate, pyruvate, creatinine, acylcarnitines — in the diagnosis of mitochondrial dysfunction. The aim of the work: to improve the diagnostic panel of biomarkers for mitochondrial disorders in children based on a number of potential laboratory parameters, such as FGF-21 and GDF-15 lactate, pyruvate, creatinine, acylcarnitines. Materials and methods. Eighty-two patients aged 1 to 17 years were analyzed. The levels of these biomarkers were measured in patients with suspected mitochondrial diseases. For each biomarker, sensitivity and specificity, area under the curve (AUC) were calculated. Results. FGF-21 showed an AUC of 0.862 ± 0.091 and a sensitivity of 80% in patients with mitochondrial disorders, with specificity ranging from 88 to 100%. GDF-15 demonstrated the highest AUC among the studied biomarkers (0.898 ± 0.103), a sensitivity of 0.92, and a specificity of 91 to 100%, indicating its particularly high efficacy. The study of lactate revealed that with its increased level, there is a sensitivity of 75% in patients with mitochondrial disorders (MD), which was confirmed in 37 cases out of 52, and a specificity from 85 to 100%, the average AUC was 0.861 ± 0.049, and for creatinine with an increased level, the sensitivity was lower and was 35.7% (19 out of 52 children with MD. For pyruvate, AUC was 0.835 ± 0.106, confirming its usefulness as an additional biomarker together with lactate. Conclusion. The studies have shown that the new indicators FGF-21 and GDF-15 are particularly distinguished by their diagnostic value and can be recommended for wide use in medical practice.