怀化地区新生儿脂肪酸氧化代谢病筛查及随访分析

目的了解怀化市新生儿脂肪酸氧化代谢病(FAOD)的患病率及预后。方法回顾性分析怀化市2015年3月—2017年12月应用串联质谱技术进行筛查的新生儿79 205例,应用串联质谱技术检测血片酰基肉碱水平,初筛阳性者立即召回复查,复查阳性者应用气相色谱-质谱进行尿有机酸分析及高精准度二代测序技术(NGS)以明确诊断。并对确诊患儿的预后进行分析。结果在79 205例新生儿中筛查并诊断脂肪酸氧化代谢病9例,分别是B-酮硫解酶缺乏症1例,短链酰基辅酶A脱氢酶缺乏症5例,原发性肉碱缺乏症2例,极长链酰基辅酶A脱氢酶缺乏症1例。结论 FAOD在怀化市新生儿中以短链酰基辅酶A脱氢酶缺乏症最常见。随访2~26个月,死亡1例(极长链酰基辅酶A脱氢酶缺乏症)。串联质谱方法是诊断新生儿脂肪酸氧化代谢病的快速有效方法,其检测结果可为患儿的早期诊断和治疗提供依据。     

甘肃地区1例短链酰基辅酶A脱氢酶缺乏症的诊断和基因突变分析

目的 探讨甘肃地区1例疑似新生儿短链酰基辅酶A脱氢酶缺乏症（SCADD）患儿的新发基因突变特点和诊断依据。方法 对2022年1—12月60150例新生儿利用串联质谱技术，检测滤纸片干血斑酰基肉碱水平，通过尿有机酸气相质谱检测技术及短链酰基辅酶A脱氢酶（ACADS）基因突变分析进一步诊断。结果 发现1例SCADD高度可疑患儿，该患儿血串联质谱丁酰基肉碱（C4），及其与丙酰基肉碱（C3）和乙酰基肉碱（C2）的比值均增高；尿气相质谱乙酰甘氨酸和乙基丙二酸明显增高；全外显基因测序发现短链酰基辅酶A脱氢酶（ACADS）基因c.164C>T和c.1030-7T>G两个位点突变。结论 通过血串联质谱技术可以筛出可疑SCADD患儿，配合尿有机酸测定和基因检测可明确诊断该代谢病，进而早干预，减少相关临床症状。     

盐城地区新生儿遗传代谢病串联质谱筛查结果回顾性分析

目的探讨串联质谱技术在遗传代谢病筛查和诊断中的意义,初步了解江苏省盐城市新生儿遗传代谢病发病率及病种分布情况。方法对盐城市2014年6月至2015年6月所有参与新生儿疾病筛查的新生儿在出生72h后充分哺乳,由专业医务人员采集足跟血制成滤纸干血片样本,应用串联质谱技术和非衍生化实验方法,检测样品中的氨基酸、酰基肉碱、琥珀酰丙酮等指标,筛查氨基酸、有机酸、脂肪酸氧化代谢病等27种疾病,对可疑结果进行复检和召回复查,对高度可疑结果进行确诊和跟踪随访。结果共筛查新生儿78904例,其中可疑阳性693例(0.9%),确诊18例,发病率1/4384。其中高苯丙氨酸血症10例,发病率1/7890;高脯氨酸血症3例,发病率1/26301;原发性肉碱缺乏症、瓜氨酸血症I型、甲基丙二酸血症、短链酰基辅酶A脱氢酶缺乏症、异丁酰辅酶A脱氢酶缺乏症各1例,发病率分别为1/78904,此外发现有明显生化表现的高苯丙氨酸血症致病突变携带者2例和原发性肉碱缺乏症致病突变携带者1例。结论应用串联质谱技术进行新生儿筛查可及时发现遗传代谢病患儿,具有一次检测同时筛查多种疾病的特点,这对降低本地出生人口缺陷,提高出生人口素质,是十分必要的。     

临沂地区新生儿遗传代谢病串联质谱结果分析

目的探讨串联质谱技术在新生儿遗传代谢病筛查和诊断中的作用和意义,统计并了解我市遗传代谢病发病率。方法收集2014年7月～2017年9月临沂市出生的新生儿足跟血干血滤纸片,通过串联质谱技术检测样本中氨基酸及酰基肉碱等指标,以筛查氨基酸、有机酸和脂肪酸代谢病共48种遗传代谢病,可疑阳性者进一步确诊。结果共筛查83 570例新生儿,可疑阳性2002例,确诊16例,包括氨基酸代谢病1例(高甲硫氨酸血症),有机酸代谢病6例(甲基丙二酸血症5例,戊二酸血症Ⅰ型1例),脂肪酸代谢病9例(原发性肉碱缺乏症7例、短链酰基辅酶a脱氢酶缺乏症2例)。结论应用串联质谱技术在全市范围内筛查并确诊16例病例,实现了新生儿遗传代谢病早发现早治疗的目的,有效保障儿童健康,降低出生缺陷,提高出生人口素质。     

儿童扩张性心肌病伴脂肪酸氧化代谢异常9例

目的探讨儿童扩张性心肌病伴脂肪酸氧化代谢异常的临床特征、诊断与治疗。方法回顾性分析2007年1月至2011年6月在首都医科大学附属北京安贞医院诊断为扩张性心肌病伴脂肪酸氧化代谢异常患儿的临床特征、实验室检查、治疗和随访情况。结果 9例扩张性心肌病伴脂肪酸氧化代谢异常患儿进入分析,男5例,女4例。病程0.5-4.5年,起病年龄11个月至18岁。9例均有乏力表现,4例合并肌肉无力,1例四肢近端肌萎缩,2例有惊厥发作,2例伴生长发育落后。9例均有不同程度肝肿大,8例肝功能异常,7例CK、CK-MB和乳酸脱氢酶增高,6例乳酸增高,2例低血糖,3例高血氨。9例超声心动图检查均可见左心室舒张末期内径增高和射血分数下降。肌电图示肌源性损害2例。串联质谱检查示游离肉碱明显增高1例,减少5例,正常3例;酯酰肉碱增高7例,减少1例,正常1例。临床诊断肉毒碱棕榈酰转移酶Ⅰ缺乏症1例,原发性肉碱缺乏症1例,多种酰基辅酶A脱氢酶缺乏4例,长链酰基辅酶A脱氢酶缺乏3例。9例在常规抗心力衰竭治疗基础上,补充左旋肉碱、维生素及低脂肪、预防饥饿等饮食指导。随访0.5-3年,临床症状、生化指标和超声心动图表现逐渐改善。结论原因不明的心脏扩大合并多系统症状和生化指标异常者,应考虑到脂肪酸代谢异常可能,及早进行代谢病筛查,早期诊断和合理治疗是改善预后的关键。     

液相串联质谱在遗传代谢病高危新生儿检测中运用研究

目的研究液相串联质谱在遗传代谢病高危新生儿检测中的意义。方法留取560例临床疑似遗传代谢病新生儿的干血滤纸片,经含氨基酸、酰基肉碱内标的甲醇萃取,盐酸正丁醇衍生后,进行液相串联质谱分析。结果560例高危新生儿中检测出患儿48例,阳性率8．6％（48／560）,包括脂肪酸代谢病11例（22．9％）;氨基酸代谢病15例（31．3％）;有机酸代谢病22例（45．8％）。结论液相串联质谱可以通过检测血滤纸片中的不同酰基肉碱浓度,一次分析快速检测30多种遗传代谢病,对于遗传代谢病高危新生儿的临床诊断具有重要的价值。     

新生儿短链酰基辅酶A脱氢酶缺乏症4例临床特征及基因突变分析

目的探讨青岛地区新生儿短链酰基辅酶A脱氢酶缺乏症(SCADD)患儿的临床特征及基因突变特点。方法利用串联质谱技术检测283 104名新生儿干血滤纸片中酰基肉碱水平,对筛查出的疑似SCADD患儿通过尿有机酸检测、短链酰基辅酶A脱氢酶(ACADS)突变检测进行确诊。结果共确诊4例短链酰基辅酶A脱氢酶缺乏症患儿,患病率1. 4/10万(1/70 776)。患儿临床表现无明显异常,串联质谱检测显示血丁酰基肉碱(C4)及其与乙酰肉碱(C2)、丙酰肉碱(C3)比值均增高。对4例患儿进行尿有机酸分析,乙基丙二酸均增高[8. 41～36. 34 mg/g肌酐(正常值0～6. 20 mg/g肌酐)],还有2例伴乳酸增高,1例伴丙酮酸增高。基因测序共发现7种ACADS突变,4种为已知突变,3种未报道突变,均为错义突变。4例患儿均为复合杂合突变,分别为:c. 1031AG/c. 989GA; c. 1186GA/c. 1195CT; c. 1031AG/c. 445AT; c. 1130CT/c. 1157GA。常见突变为c. 1031AG(25%),ACADS基因型与乙基丙二酸以及C4浓度水平无明显相关。对患儿进行饮食指导,随访均未出现临床症状,体格及智力发育正常。结论通过血串联质谱筛查配合基因测序可以对SCADD明确诊断,早期确诊的新生儿无临床症状,预后较好。     

4819例遗传代谢病检测结果分析

目的 为了解遗传代谢病的发病率,以便推动遗传代谢病的全面筛查,应用液相色谱-串联质谱(liquid chromatography-tandem mass spectrometry,LC-MS/MS)检测血氨基酸和酰基肉碱,联合气相色谱-串联质谱(gas chromatography-tandem mass spectrometry,GC-MS)技术检测尿液中有机酸,对氨基酸、有机酸代谢病及脂肪酸β氧化障碍进行筛查和诊断.方法 收集4819例(包括1388例新生儿及3431例疑似遗传代谢病高危儿童)血氨基酸和酰基肉碱检测结果及尿有机酸检测结果,分别利用LC-MS/MS检测了4778例干滤纸片和GC-MS检测了3004例尿标本.结果 通过遗传代谢病筛查共确诊88例(占所检测样本的1.83%,这88例均行LC-MS/MS和GC-MS检测),其中氨基酸代谢病9种,37例;有机酸代谢病7种,40例;脂肪酸β氧化障碍5种,11例.结论 联合LC-MS/MS及GC-MS能快速对遗传代谢病进行筛查和诊断.     

四例极长链酰基辅酶A脱氢酶缺乏症患儿的串联质谱及基因变异分析

目的:探讨4例极长链酰基辅酶A脱氢酶(very long chain acyl-coenzyme A dehydrogenase,VLCAD)缺乏症的临床特征及基因变异特点。方法:对新生儿筛查中十四烯酰基肉碱(C14：1)≥0.4 μmol/L的新生儿召回复查,通过串联质谱、基因检测确诊4例VLCAD缺乏症患儿,对确诊...     

两种质谱技术在小儿重症遗传代谢病诊断的应用及评价

目的探讨小儿重症监护病房遗传代谢病的发生率,评价气相色谱-质谱(GC-MS)和串联质谱技术(MSMS)对遗传代谢性疾病的应用价值。方法选取2015年1月-2018年10月我院收治的重症遗传代谢性疾病患儿43例,采用GCMS、MS-MS技术进行诊断,分析患儿主要临床症状表现以及预后。我们将所有病例进行两种方式进行检测。结果 43例代谢性疾病患儿临床表现为反复代谢性酸中毒,意识障碍,严重电解质紊乱,不明原因肝功能障碍,黄疸,凝血功能障碍,血氨增高等主要症状;发现用GC-MS检测尿标本阳性24例,阳性率为55.81%,用MS-MS检测血标本检测出阳性30例,阳性率为69.77%。结合基因等实验室方法检查结果最终确诊为:甲基丙二酸血症9例,原发性肉碱缺乏症4例,希特林蛋白缺乏症2例,β酮硫解酶缺乏4例,线粒体疾病3例,尼曼匹克病3例,高苯丙酸血症2例,糖原累积病2例,多种酰基辅酶A脱氢酶缺乏症2例,生物素酶缺乏症2例,鸟氨酸氨甲酰基转移酶缺乏症2例,酪氨酸血症2例,枫糖血症1例,戊二酸血症1例,异戊酸血症1例,极长链酰辅酶A脱氢酶缺乏症1例,肉碱棕榈酰转移酶缺乏症1例,粘多糖贮积症1例,肝豆状核变性1例。以上疾病症状都较为隐匿,不易发现,在临床诊治中容易出现误诊、漏诊。结论小儿重症监护病房遗传代谢病临床分析过程中,患儿主要表现为发育落后,喂养困难,意识障碍,惊厥,严重代酸等。对患儿尽早进行血、尿标本遗传代谢病筛查,两种方法不能互为代替。但部分疾病的确诊往往要结合基因检查等实验室检查结果进行综合分析才能做出,及时合理治疗能挽救更多危重患儿并改善预后。     

Maternal medium-chain acyl-CoA dehydrogenase deficiency identified by newborn screening

Prior to the advent of expanded newborn screening, sudden and unexplained death was often the first and only symptom of medium-chain acyl-CoA dehydrogenase deficiency (MCADD). With the use of tandem mass spectrometry, infants can now be identified and treated before a life threatening metabolic decompensation occurs. Newborn screening has also been shown to detect previously undiagnosed maternal inborn errors of metabolism. We have now diagnosed two women with MCADD following the identification of low free carnitine in their newborns. While one of the women reported prior symptoms of fasting intolerance, neither had a history of metabolic decompensation or other symptoms consistent with a fatty acid oxidation disorder. These cases illustrate the importance of including urine organic acid analysis and an acylcarnitine profile as part of the confirmatory testing algorithm for mothers when low free carnitine is identified in their infants.     

Development of a newborn screening follow-up algorithm for the diagnosis of isobutyryl-CoA dehydrogenase deficiency.

PURPOSE: Isobutyryl-CoA dehydrogenase deficiency is a defect in valine metabolism and was first reported in a child with cardiomyopathy, anemia, and secondary carnitine deficiency. We identified 13 isobutyryl-CoA dehydrogenase-deficient patients through newborn screening due to an elevation of C4-acylcarnitine in dried blood spots. Because C4-acylcarnitine represents both isobutyryl- and butyrylcarnitine, elevations are not specific for isobutyryl-CoA dehydrogenase deficiency but are also observed in short-chain acyl-CoA dehydrogenase deficiency. To delineate the correct diagnosis, we have developed a follow-up algorithm for abnormal C4-acylcarnitine newborn screening results based on the comparison of biomarkers for both conditions. METHODS: Fibroblast cultures were established from infants with C4-acylcarnitine elevations, and the analysis of in vitro acylcarnitine profiles provided confirmation of either isobutyryl-CoA dehydrogenase or short-chain acyl-CoA dehydrogenase deficiency. Isobutyryl-CoA dehydrogenase deficiency was further confirmed by molecular genetic analysis of the gene encoding isobutyryl-CoA dehydrogenase (ACAD8). Plasma acylcarnitines, urine acylglycines, organic acids, and urine acylcarnitine results were compared between isobutyryl-CoA dehydrogenase- and short-chain acyl-CoA dehydrogenase-deficient patients. RESULTS: Quantification of C4-acylcarnitine in plasma and urine as well as ethylmalonic acid in urine allows the differentiation of isobutyryl-CoA dehydrogenase-deficient from short-chain acyl-CoA dehydrogenase-deficient cases. In nine unrelated patients with isobutyryl-CoA dehydrogenase deficiency, 10 missense mutations were identified in ACAD8. To date, 10 of the 13 isobutyryl-CoA dehydrogenase-deficient patients remain asymptomatic, two were lost to follow-up, and one patient required frequent hospitalizations due to emesis and dehydration but is developing normally at 5 years of age. CONCLUSION: Although the natural history of isobutyryl-CoA dehydrogenase deficiency must be further defined, we have developed an algorithm for rapid laboratory evaluation of neonates with an isolated elevation of C4-acylcarnitine identified through newborn screening.     

Diagnostic pitfall in antenatal manifestations of CPT II deficiency

Carnitine palmitoyltransferase II (CPT2) deficiency is a rare inborn error of mitochondrial fatty acid metabolism associated with various phenotypes. Whereas most patients present with postnatal signs of energetic failure affecting muscle and liver, a small subset of patients presents antenatal malformations including brain dysgenesis and neuronal migration defects. Here, we report recurrence of severe cerebral dysgenesis with Dandy–Walker malformation in three successive pregnancies and review previously reported antenatal cases. Interestingly, we also report that acylcarnitines profile, tested retrospectively on the amniotic fluid of last pregnancy, was not sensitive enough to allow reliable prenatal diagnosis of CPT2 deficiency. Finally, because fetuses affected by severe cerebral malformations are frequently aborted, CPT2 deficiency may be underestimated and fatty acid oxidation disorders should be considered when faced with a fetus with Dandy–Walker anomaly or another brain dysgenesis.     

Neonatal carnitine palmitoyltransferase II deficiency associated with Dandy-Walker syndrome and sudden death

Neonatal onset of carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive, often lethal disorder of the mitochondrial beta-oxidation of long-chain fatty acids. It is a rare multiorgan disease which includes hypoketotic hypoglycemia, severe hepatomuscular symptoms, cardiac abnormalities, seizures and lethargy, as well as dysmorphic features. Until now, only 22 affected families have been described in the literature.An increasing number of mutations are being identified in the CPT2 gene, with a distinct genotype–phenotype correlation in most cases. Herein we report a new case of neonatal CPT II deficiency associated with Dandy-Walker syndrome and sudden death at 13 days of life. CPT II deficiency was suggested by acylcarnitine analysis of dried-blood on filter paper in the expanded newborn screening. Genetic analysis of the CPT2 gene identified the presence of a previously described mutation in homozygosity (c.534_558del25bpinsT).All lethal neonatal CPT II deficiency patients previously described presented severe symptoms during the first week of life, although this was not the case in our patient, who remained stable and without apparent vital risk during the first 11 days of life.The introduction of tandem mass spectrometry to newborn screening has substantially improved our ability to detect metabolic diseases in the newborn period. This case illustrates the value of expanded newborn screening in a neonate with an unusual clinical presentation, combining hydrocephalus and sudden death, that might not commonly lead to the suspicion of an inborn error of metabolism.     

Effect of sports activity on carnitine metabolism. Measurement of free carnitine, gamma-butyrobetaine and acylcarnitines by tandem mass spectrometry.

The effects of sports activity on carnitine metabolism were studied using mass spectrometry. Serum levels of free carnitine, acylcarnitines (acetylcarnitine, propionylcarnitine, C4-, C5- and C8-acylcarnitine) and gamma-butyrobetaine, a carnitine precursor, were determined by tandem mass spectrometry in liquid secondary ion mass ionization mode. The coefficients of variation at three different concentrations were 2.8-7.9% for gamma-butyrobetaine, and 1.2 to approximately 6.7% for free carnitine. The recoveries added to serum were 109.1% for gamma-butyrobetaine, 89.3% for free carnitine. Sports activity caused increased serum levels of gamma-butyrobetaine, acetylcarnitine, C4- and C8-acylcarnitines and decreased serum levels of free carnitine. This method requires a small amount of sample volume (20 microl of serum) and short total instrumental time for the analysis (1 h for preparation, 2 min per sample for mass spectrometric analysis). Therefore, this method can be applied to study carnitine metabolism under various conditions that affect fatty acid oxidation.     

Commentary on a delphi clinical practice protocol for the diagnosis and management of very long chain acyl-CoA dehydrogenase deficiency by Arnold et al.

Very long chain acyl-CoA dehydrogenase deficiency (VLCAD) can now be detected by newborn screening by tandem mass spectrometry. The incidence is higher than previously estimated because of the identification of potentially milder later onset variants by screening. Although there is little information in the literature on the optimal management of rare inborn errors, there is a need for management guidelines, especially for non-specialist providers in the community. In the accompanying article, Arnold et al. present a diagnostic and management guideline for VLCAD, developed by the Delphi method for gaining consensus from a panel of 14 metabolic specialists. While consensus was gained for some issues, there was no clear consensus for several important management issues, particularly for the later onset variants. Clearly, there is an urgent need for multinational collaborative protocol driven outcomes studies that will provide the data necessary to establish robust guidelines for inborn errors of metabolism.     

Expanded newborn screening identifies maternal primary carnitine deficiency

Primary carnitine deficiency impairs fatty acid oxidation and can result in hypoglycemia, hepatic encephalopathy, cardiomyopathy and sudden death. We diagnosed primary carnitine deficiency in six unrelated women whose unaffected infants were identified with low free carnitine levels (C0) by newborn screening using tandem mass spectrometry. Given the lifetime risk of morbidity or sudden death, identification of adult patients with primary carnitine deficiency is an added benefit of expanded newborn screening programs.     

Choice of oils for essential fat supplements can enhance production of abnormal metabolites in fat oxidation disorders

Patients with mitochondrial long-chain fat oxidation deficiencies are usually treated with diets containing reduced fat and increased carbohydrate, at times via gastrostomy feeding. To ensure adequate intake of essential fatty acids, supplements are provided to their diets using commercially available oils. These oils contain large quantities of non-essential fats that are preferentially oxidized and produce disease-specific metabolites (acyl-CoA intermediates) due to the genetic defect. This study describes the concentrations of these intermediates as reflected by acylcarnitines as well as the % contribution from each of four fatty acids: palmitate, oleate, linoleate, and alpha-linolenate when incubated with fibroblasts from patients with VLCAD, LCHAD, and trifunctional protein (TFP) deficiencies. Palmitate and oleate produce the majority of disease-specific acylcarnitines with these defective cell lines (79-94%) whereas linoleate and linolenate produced less (6-21%). On average, the amount of acylcarnitines decreased with increasing unsaturation (C18:1>C18:2>C18:3:34%>11%>3%, respectively. This relationship may reflect the "gatekeeper" role of carnitine palmitoyltransferase I (CPT I). A diet comparison between Canola and a combination of Flax/Walnut oils revealed that the latter, containing the least amount of non-essential fats, reduced blood acylcarnitine levels by 33-36%. The etiology of the severe peripheral neuropathy of TFP deficiency may result from the unique metabolite, 3-keto-acyl-CoA, after conversion to a methylketone via spontaneous decarboxylation. Essential fatty acid supplementation with oils should consider these findings to decrease production of disease-specific acyl-CoA intermediates.