Neonatal carnitine-acylcarnitine translocase deficiency in newborn: clinical features and gene mutation

Objective To investigate the clinical features of carnitine-acylcarnitine translocase deficiency (CACTD) and mutation of the gene SLC25A20 (solute carrier family126 25 member 20) in newborn. Methods The clinical features of a newborn with CACTD were analyzed. Mass spectrometry was used to detect the blood acylcarnitine and urine organic acid metabolites in the child. Sanger direct sequencing was used to detect the 9 exons of SLC25A20 gene in the child and his parents. The CNKI, Wanfang and PubMed databases were retrieved. The clinical features and gene mutation loci in CACTD neonates reported in China and worldwide were compared. Results In this male patient, CACTD occurred hours after birth, presenting cyanosis, malignant arrhythmia, cardiac arrest, convulsion, hypoketotic hypoglycemia, hyperammonemia, and hyperlactosis. Head magnetic resonance showed signs of metabolic encephalopathy. His blood acylcarnitine tested a low level of free carnitine and a high level of long-chain acylcarnitine. Gene sequencing showed that the patient was a homozygous mutant, and both of his parents were heterozygous mutants, for carnitine SLC25A20 c. 199-10T>G. A total of 41 known pathogenic mutations of the SLC25A20 gene were reported in the literature, with the c. 199-10T>G mutation commonly seen in East Asia. So far 12 CACTD patients with c. 199-10T>G mutation have been reported, all identified early in neonates, clinically manifested by cardiac arrest, respiratory failure, convulsion, feeding difficulties, and with high mortality rate. Conclusion Early onset and rapid deterioration of arrhythmia, hypoglycemia, hyperlactosis, and convulsions in newborns should highly alert for a probable diagnosis of CACTD or other fatty acid oxidation disorders, and prompt for timely testing of blood acylcarnitine, urine gas chromatography-mass spectrometry (GC-MS) , and carnitine SLC25A20 gene profiling in order to make a clear diagnosis. Key words: Fatty acid oxidation disorder; Carnitine acylcarnitine translocase; SLC25A20; Infant, newborn