Objective:To explore the clinical phenotype, diagnosis, treatment and genetic characteristics of infants with lethal mitochondrial trifunctional protein deficiency (MTPD).Methods:The clinical data of one patient with lethal MTPD admitted to the neonatal department of Guilin Maternal and Child Health Hospital were retrospectively analyzed. Relevant literature published up to July 2023 were retrieved from the Chinese Science and Technology Journal database, CNKI, Wanfang Database, Chinese Medical Journal Full-text Database, Chinese Biomedical Journal Literature Database, China Biomedical Literature Database, PubMed, Elsevier ScienceDirect, Embase and BIOSIS Previews with the terms of "mitochondrial trifunctional protein deficiency", "mitochondrial trifunctional protein", "HADHA", "HADHB", "newborn", "infant" and "lethal". Then the characteristics of clinical phenotypes and genetic variations about MTPD infants were summarized.Results:This patient was a 33 +3 week premature male infant who developed symptoms 9 d after birth. The main manifestations were metabolic acidosis, recurrent apnea, shock, cardiomyopathy and heart failure. Blood tandem mass spectrometry reported an increased levels of multiple acylcarnitines, and genetic testing indicated that the patient's HADHB gene had maternal c.527C>G missense mutation and de novo c.1148C>T missense mutation. The infant was diagnosed with lethal MTPD and died 12 d after birth after his family gave up the treatment. There were 29 cases in the total 13 publications that were retrieved. Together with this case, there were 30 cases involved. Among the 16 cases with relatively complete data, 10 cases were male and 15 cases developed symptoms in neonatal period. The main clinical phenotypes were cardiomyopathy, abnormal myocardial enzyme spectrum, heart failure and lactic acidosis or metabolic acidosis. Among the 15 cases with clear age of death, 14 died within 3 months of life. Of the reported patients, only one survived at 8 years of age. 29 cases were confirmed through genetic test, 10 infants had HADHA gene variations and 19 had HADHB gene variations. Only one patient was confirmed by pathological detection and mass spectrometry analysis. Conclusions:MTPD is a rare autosomal recessive genetic disease. Lethal MTPD has an early onset with high mortality. Severe acidosis and heart failure are the most common symptoms in neonatal period. Early detection of acylcarnitine and HADHB, HADHA gene should be performed in highly suspected infants to help early genetic diagnosis and intervention.