Objective: To investigate the clinical, biochemical and genetic features of four carnitine-acylcarnitine translocase deficiency cases. Methods: Four cases diagnosed with carnitine-acylcarnitine translocase deficiency from Guangxi Maternal and Child Health Hospital were studied. DNA was extracted from dry blood filter for gene analysis. SLC25A20 gene analysis was performed in 1 case and the whole exon sequence analysis was performed in 3 cases. Results: Retrospective study on unrelated carnitine-acylcarnitine translocase deficiency patients, the age of onset was 1-28 d, the age of death were 1.5-30 d, main clinical features were hypoglycemia (4 cases), arrhythmia (2 cases), sudden death (2 cases). Biochemical test showed hypoglycemia (1.2-2.0 mmol/L) , elevated creatine kinase (955-8 361 U/L) and creatine kinase isozyme(199-360 U/L), normal or decreased free carnitine level (3.70-27.07 μmol/L) , elevated long-chain acylcarnitine (palmityl carnitine 1.85-14.84 μmol/L). The gene tests showed that all 4 cases carried SLC25A20 gene c.199-10T> G homozygous mutation, inherited from their parents. By analyzing the haplotype, we found that the mutation loci of C. 199-10T> G were all in the same haplotype. Conclusion: The c.199-10T> G mutation is an important molecular cause of carnitine-acylcarnitine translocase deficiency, which has relatively high frequency in Guangxi population, and is related to the founder effect.
目的： 探讨肉碱-酰基肉碱移位酶缺乏症临床、生化以及基因变异特点。 方法： 对2014-2017年在广西壮族自治区妇幼保健院遗传代谢中心实验室确诊的4例肉碱-酰基肉碱移位酶缺乏症患儿的临床表现、生化检查、基因检测结果进行回顾性分析。4例患儿均通过干血滤纸片提取基因组DNA进行基因分析，其中1例患儿进行SLC25A20基因分析，3例患儿进行全外显子组测序分析。 结果： 4例无亲缘关系的患儿发病年龄1~28 d，死亡年龄1.5~30 d，临床表现为新生儿低血糖（4例）、心律失常（2例）、猝死（2例），生化检查：血糖1.2~2.0 mmol/L、肌酸激酶955~8 361 U/L，肌酸激酶同工酶199~360 U/L，游离肉碱3.70~27.07 μmol/L，棕榈酰肉碱1.85~14.84 μmol/L。4例患儿均携带SLC25A20基因c.199-10T>G纯合变异，父母为杂合变异携带者。通过构建单体型发现，c.199-10T>G变异位点均处于同一单体型。 结论： 肉碱-酰基肉碱移位酶缺乏症临床表现急重，预后不佳。表现有低血糖、心肌酶升高，长链酰基肉碱升高。c.199-10T>G变异是肉碱-酰基肉碱移位酶缺乏症的重要分子病因，单体型分析提示该变异与奠基者效应有关。.
Keywords: Carnitine acyltransferases; Metabolism, inborn errors.