Primary Carnitine Deficiency Presents Atypically with Long QT Syndrome: A Case Report
Primary Carnitine Deficiency Presents Atypically with Long QT Syndrome: A Case Report
复制标题
DOI：
10.1007/8904_2011_52
复制
发表时间：
2012-01-01
期刊：
影响因子：
--
通讯作者：
Wood, Tim
中科院分区：
文献类型：
--
作者：
De Biase, Irene;Champaigne, Neena Lorenzana;Wood, Tim
原发性肉碱缺乏症(PCD)是一种常染色体隐性脂肪酸氧化障碍，由编码肉碱转运蛋白OCTN2的SLC22A5基因突变引起。肉碱摄取不足导致肾脏肉碱消耗和血浆低水平。PCD通常在生命早期表现为急性代谢危机或进行性心肌病，对肉碱补充有反应。将PCD纳入新生儿筛查(NBS)计划已导致确认无症状的成年患者，因为他们的后代NBS呈阳性。我们广泛查阅文献，发现42例成人病例中有15例(35.7%)有症状。5例患者出现心律失常(12%)。在这里，我们报告了第一例PCD表现为长QT综合征的确诊和长期随访。患者在20岁出头时出现室性心动过速引起的突触发作，QT间期延长。心律失常在药物治疗中控制不佳，安装了除颤器。在她的第一次怀孕期间，突触发作升级。患者孩子的NBS阳性提示肉碱摄取不足，肉碱转运蛋白活性降低和分子检测证实了这一点。开始补充肉碱后，没有再发生突触发作，QT间期恢复正常。作为预防措施，小剂量美托洛尔治疗和除颤器仍在使用中。虽然很少见，但PCD应该被排除为心律失常的原因，因为口服肉碱补充是容易获得和有效的。
Primary carnitine deficiency (PCD) is an autosomal recessive disorder of fatty acid oxidation caused by mutations in the SLC22A5 gene encoding for the carnitine transporter OCTN2. Carnitine uptake deficiency results in renal carnitine wasting and low plasma levels. PCD usually presents early in life either with acute metabolic crisis or as progressive cardiomyopathy that responds to carnitine supplementation. PCD inclusion in the newborn screening (NBS) programs has led to the identification of asymptomatic adult patients ascertained because of a positive NBS in their offspring. We extensively reviewed the literature and found that 15 of 42 adult published cases (35.7%) were symptomatic. Cardiac arrhythmias were present in five patients (12%). Here, we report the ascertainment and long-term follow-up of the first case of PCD presenting with long QT syndrome. The patient presented in her early twenties with a syncopal episode caused by ventricular tachycardia, and a prolonged QT interval. Arrhythmias were poorly controlled by pharmacologic therapy and a defibrillator was installed. Syncopal episodes escalated during her first pregnancy. A positive NBS in the patient's child suggested a carnitine uptake deficiency, which was confirmed by reduced carnitine transporter activity and by molecular testing. After starting carnitine supplementation, no further syncopal episodes have occurred and the QT interval returned to normal. As precaution, a low-dose metoprolol therapy and the defibrillator are still in place. Although rare, PCD should be ruled out as a cause of cardiac arrhythmias since oral carnitine supplementation is readily available and efficient.