Objectives: Disorders of mitochondrial energy metabolism can show all inheritance patterns and new genes and associated mitochondrial disorders continue to be identified. In the absence of definitive pathognomic clinical features, elevated mitochondrial biomarkers or neuroimaging findings can be diagnostic clues. However, a diagnosis of mitochondrial disease often cannot be confirmed until potential pathogenic variants associated with mitochondrial disease are defined by an exome or genome analysis. Approximately 85-90% of primary mitochondrial diseases in childhood are associated with nuclear gene mutations. This study aimed to evaluate the genotype-phenotype correlation in childhood mitochondrial diseases in our region.

Methods: We retrospectively analyzed the symptoms, laboratory investigations, imaging, and mutations of 34 patients with a consecutively confirmed genetic diagnosis of mitochondrial disease between 2011 and 2022.

Results: The most common complaint was gait disturbance presenting 19 males (55.8%) aged between 5 months and 17 years. Other common symptoms were flaccidity, decline in motor skills, and visual impairment, respectively. The patients' plasma lactate and CK levels were elevated at 40% (n:14) and 31.4% (n:11), respectively. Mitochondrial disease-compatible appearance on brain MR imaging was observed in 19 patients. Mitochondrial disease associated with nuclear DNA mutation was detected in 76.4% (n:26) of the patients. The most common mutations were MFN2, OPA1, RMND1, SUCLA2 and SLCA193, respectively.

Conclusion: We aimed to reveal the genetic, clinical and geographical differences in mitochondrial diseases seen in children in the Eastern Mediterranean region of Turkey.

İlknur EROL

Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center, Department of Pediatric Neurology

Department of Pediatric Neurology

Adana, Turkey

Elif Perihan ONCEL

Child Neurologist, Dr.

Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center, Department of Pediatric Neurology

Department of Pediatric Neurology

Adana Turkey

Şeyda BESEN

Baskent University Faculty of Medicine, Adana Dr. Turgut Noyan Application and Research Center, Department of Pediatric Neurology

Department of Pediatric Neurology

Adana Turkey

Serdar CEYLANER

Clinical Genetics Unit

Intergen Genetics and Rare Diseases Diagnosis Research & Application Center, Clinical Genetics Unit

Ankara, Turkey

Sevcan TUG BOZDOGAN

Medical Genetics Department of Medical Faculty

Cukurova University AGENTEM (Adana Genetic Diseases Diagnosis and Treatment Center) and Medical Genetics Department of Medical Faculty