中、短链酰基辅酶A脱氢酶缺乏症患儿临床特点分析及基因突变研究

An analysis of clinical characteristics and gene mutation in two patients with medium- and short-chain acyl-Co A dehydrogenase deficiency

中、短链酰基辅酶A脱氢酶缺乏症属脂肪酸β氧化障碍疾病,其基因突变可导致中、短链脂肪酸无法进入线粒体进行氧化供能,引起多器官功能异常。本研究对2例临床表现为低血糖合并代谢性酸中毒的患儿进行血酰基肉碱及尿液有机酸分析,同时对患儿及其父母进行基因突变检测。家系1患儿,男,3 d,出生后因新生儿窒息、吸奶无力、嗜睡住院治疗。血酰基肉碱谱提示中链酰基肉碱（C6~C10）升高,其中辛酰肉碱（C8）3.52μmol/L（参考值0.02~0.2μmol/L）;尿有机酸分析未见明显异常;Sanger测序发现ACADM基因7号外显子已报道纯合突变c.580A〉G（p.Asn194Asp）。家系2患儿,女,3个月,因咳嗽伴反复发热10余天住院治疗。血酰基肉碱谱提示血丁酰肉碱（C4）1.66μmol/L（参考值0.06~0.6μmol/L）;尿有机酸分析提示乙基丙二酸55.9（参考值0~6.2）;Sanger测序发现ACADS基因已报道纯合突变c.625G〉A（p.Gly209Ser）。研究结果提示对不明原因代谢性酸中毒及低血糖患儿应进行遗传代谢病筛查,通过家系ACADM、ACADS基因分析,将有助于中、短链酰基辅酶A脱氢酶缺乏症的诊断。

Medium- and short-chain acyl-CoA dehydrogenase deficiency is a disorder of fatty acid β-oxidation. Gene mutation prevents medium- and short-chain fatty acids from entry into mitochondria for oxidation, which leads to multiple organ dysfunction. In this study, serum acylcarnitines and the organic acid proifle in urea were analyzed in two children whose clinical symptoms were hypoglycemia and metabolic acidosis. Moreover, gene mutations in the two children and their parents were evaluated. One of the patients was a 3-day-old male who was admitted to the hospital due to neonatal asphyxia, sucking weakness, and sleepiness. The serum acylcarnitine proifle showed increases in medium-chain acylcarnitines （C6-C10）, particularly in C8, which showed a concentration of 3.52 μmol/L （reference value： 0.02-0.2 μmol/L）. The analysis of organic acids in urea gave a normal result. Sanger sequencing revealed a reported c.580A〉G （p.Asn194Asp） homozygous mutation at exon 7 of the ACADM gene. The other patient was a 3-month-old female who was admitted to the hospital due to cough and recurrent fever for around 10 days. The serum acylcarnitine proifle showed an increase in serum C4 level, which was 1.66 μmol/L （reference value： 0.06-0.6 μmol/L）. The analysis of organic acids in urea showed an increase in the level of ethyl malonic acid, which was 55.9 （reference value： 0-6.2）. Sanger sequencing revealed a reported c.625G〉A （p.Gly209Ser） homozygous mutation in the ACADS gene. This study indicates that screening tests for genetic metabolic diseases are recommended for children who have unexplained metabolic acidosis and hypoglycemia. Genetic analyses of the ACADM and ACADS genes are helpful for the diagnosis of medium- and short-chain acyl-CoA dehydrogenase deifciency.