Carnitine-acylcarnitine translocase deficiency (CACTD) is a rare autosomal recessive disorder of mitochondrial fatty acid oxidation that occurs due to mutations in the SLC25A20 gene. Severe CACTD results in neonatal or infantile sudden death. Herein, we reported six patients with CACTD diagnosed based on biochemical and molecular findings from 5 unrelated families in Guangdong from 2016 to 2017. Among them, five patients presented with hypotonia, nonketotic hypoglycemia, and arrhythmia 2 days after birth, while the other patient presented with respiratory distress, hypotonia, and arrhythmia. Five of the patients died in the neonatal period. Blood acylcarnitine concentrations determination from dried blood spots (DBS) were measured by tandem mass spectrometry (MS/MS). The SLC25A20 and CPT2 gene sequences were analyzed by direct Sanger sequencing. SLC25A20 gene analysis revealed a c.199-10T>G (IVS2-10T>G) homozygous variants in four unrelated patients and a novel mutation c.199-10T>G/c.719-8_c.719-1dupCCCACAG compound heterozygous variants in twins. This report describes the clinical characteristics, biochemical findings and molecular analysis of SLC25A20 gene of patients with CACTD in Guangdong. And our results show that the c.199-10T>G is likely the most common variant of CACTD in Guangdong population as it accounts for 83% (10/12) of the observed mutant alleles. Individuals with the c.199-10T>G genotype had a severe CACTD phenotype.
Keywords: Acylcarnitines; Carnitine-acylcarnitine translocase deficiency; Newborn screening; SLC25A20 gene.
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