A Patient with Organic Acidemia, Hyperammonemia, and a FBXL4 Variant Suggesting Mitochondrial DNA Depletion Syndrome

FBXL4 defects, found in approximately 0.7% of suspected mitochondrial disease cases, lead to varied phenotypes with nonspecific facial dysmorphisms. The patient's presentation aligned with reported features, including growth delay, hypotonia, and developmental delay. Notably, the diagnosis occurred later than typical onset, highlighting the variability in disease manifestation. Treatment focused on symptom management, with dichloroacetic acid effectively addressing lactic acidosis. This case underscores the importance of considering mitochondrial diseases, particularly FBXL4-related MTDPS13, in patients presenting with metabolic disturbances and dysmorphic features. Early recognition facilitates appropriate management and genetic counseling for affected families.