Abstract: Objective To analyze the clinical and genetic characteristics of GTPBP3 gene mutation associated with mitochondrial translation defect. Methods The clinical characteristics of a female preschool child related to mitochondrial translation defect caused GTPBP3 gene mutation were concluded. And related literature was reviewed. Results The child was hospitalized for pale face, dyspnea 3 hours and convulsion once, presented with severe lactic acidosis (arterial blood gas-lactic acid was 29 mmol/L), respiratory failure, myocardial damage and stroke-like syndrome. Brain MRI showed abnormal symmetry signal of bilateral cortical spinal tract. After ventilator assisted respiration, B group of vitamins, coenzyme Q10 , L-carnitine to improve metabolism and hemodialysis, the blood lactic acid dropped markedly. Her condition was gradually improved, eventually she was discharged from hospital. This disease was confirmed by molecular genetic test. Mutation of c.785 A>C (p.Q 262 P) and c. 1169 delG (p.G 390 Efs* 16 ) were detected in GTPBP 3 gene in this child, which were inherited from her mother and father respectively. Conclusion The hereditary disease should be highly suspected in patients with these symptoms. Gene analysis can help to clarify diagnosis. Improving mitochondrial metabolism and hemodialysis, if necessary, is an effective therapeutic tool to improve metabolic crisis in these children.

Key words: GTPBP3 gene; mitochondrial diseases; lactic acidosis; respiratory failure; metabolic crisis; global developmental delay; hemodialysis; preschool child