串联质谱技术在新生儿遗传代谢病筛查中的应用

目的了解串联质谱技术(MS/MS)在新生儿遗传代谢病筛查中的应用效果。方法采用高效液相串联质谱技术对2015年7月-2016年9月在合肥市助产机构分娩的85 189例新生儿足底血干滤纸血片进行27项遗传代谢病筛查,对可疑患儿进行尿有机酸检测和静脉血二代测序基因检测以明确诊断。结果 85 189例新生儿中,共筛查出患病儿童30例,总体检出率为1/2 840。其中氨基酸代谢障碍性疾病21例,有机酸代谢障碍性疾病2例,脂肪酸代谢障碍性疾病6例,尿素循环障碍性疾病1例。结论 MS/MS可以及早有效发现遗传代谢病患儿,是新生儿疾病筛查发展的趋势,是出生缺陷防控的重要措施。     

韶关市串联质谱技术选择性筛查遗传代谢病高危患儿287例初步分析

目的 应用串联质谱（tandem mass spectrometry,MS/MS）技术进行遗传代谢病（IEM）高危儿筛查,初步了解韶关市IEM的发病种类和阳性率,为其有效防治提供科学依据.方法 利用MS/MS技术对在广东省韶关市妇幼保健院新生儿科、儿童康复科就医的287例可疑患儿的血液样本进行IEM筛查.结果 发现IEM阳性患儿83例,阳性率为28.92％,其中氨基酸代谢病24例,有机酸血症11例,脂肪酸氧化缺陷疾病48例.结论 MS/MS技术是筛查诊断IEM的可靠方法.     

台州市2000-2012年新生儿遗传代谢病筛查回顾分析

目的 分析与总结台州市2000-2012年新生儿疾病筛查状况,并探讨应用串联质谱技术(MS/MS)进行新生儿遗传代谢病筛查的可行性。方法 采用时间分辩免疫荧光分析法(DELFIA)检测血促甲状腺激素(thyroid stimulating hormone,TSH)水平筛查先天性甲状腺功能减低症(congenital hypothyroidism,CH);采用荧光法检测血苯丙氨酸(Phe)浓度筛查苯丙酮尿症(phenylketonuria,PKU); 采用串联质谱技术(MS/ MS)同时检测滤纸片中酰基肉碱和氨基酸等数十种小分子代谢物含量及其相互间比值,对26种氨基酸、有机酸、脂肪酸代谢病进行筛查。结果 2000年10月-2012年9月共筛查了台州市786 672例新生儿,其中81 086例新生儿采用串联质谱技术进行多项遗传代谢病筛查。检出CH患儿499例,PKU/BH4D 31例(其中BH4D 缺乏症2例),同型半胱氨酸缺乏症1例,有机酸血症6例,脂肪酸氧化代谢病2例。 结论 新生儿疾病筛查是避免先天性遗传代谢疾病所致智力障碍残疾发生的有效措施之一,串联质谱技术应用于新生儿疾病筛查,可发现更多遗传代谢病,是新生儿疾病筛查的发展趋势。     

应用串联质谱技术进行新生儿遗传代谢病筛查44639例结果分析

目的了解新生儿遗传代谢病的发病率和基因突变情况,探讨串联质谱技术在新生儿遗传代谢病筛查中的应用。方法应用串联质谱技术对2013年8月-2014年12月泰安地区44 639例新生儿进行遗传代谢病筛查,初筛阳性者立即召回复查,依然阳性者应用气相色谱-质谱联用分析尿中的有机酸、氨基酸、肉碱等代谢产物,并且应用高精准度DNA质谱仪检测阳性患儿的突变基因。结果 44 639例新生儿中初筛阳性381例,阳性率8.53‰。确诊患儿13例,短链酰基辅酶A脱氢酶缺乏症3例,极长链酰基辅酶A脱氢酶缺乏症1例,甲基丙二酸血症4例,瓜氨酸血症I型1例,戊二酸血症I型1例,精氨酸血症1例,苯丙酮尿症2例。发病率分别是1/14 880、1/44 639、1/11 160、1/44 639、1/44 639、1/44 639、1/22 320。结论串联质谱技术在新生儿遗传代谢病筛查中起到早发现,进而可以早诊断、早治疗的作用,有效减少病残儿的发生,是预防遗传代谢病危害的有效途径。     

串联质谱分析在遗传代谢病高危儿童中的意义

目的研究末梢血串联质谱分析对于遗传代谢病高危儿童的诊断价值。方法本研究自2010年1月-2013年12月收集临床疑似遗传代谢病的病例617例,对末梢血进行氨基酸、酰基肉碱串联-质谱筛查,对筛查阳性的病例进行了尿代谢筛查或基因检测,得到了确诊。并总结分析了相关临床数据。结果 617例病例共诊断出遗传代谢病10种,共24例,总阳性率3.9%,其中氨基酸代谢病4例(16.7%),以瓜氨酸血症多见(3例,12.5%),有机酸代谢病14例(58.3%),以甲基丙二酸血症多见(8例,33.3%);脂肪酸氧化障碍6例(25%),以中链酰基辅酶A脱氢酶缺乏症、线粒体脑肌病多见(各2例,8.3%)。结论儿科医生应重视对遗传代谢病高危儿童进行末梢血氨基酸、酰基肉碱串联质谱分析以达到早诊断,早干预的目的。     

小儿高氨血症204例临床分析

目的探讨小儿高氨血症病因,增强认知,为早期诊治提供参考。方法回顾性分析2014年1月至2016年6月儿科病房和重症监护室收治患儿中,筛查符合高氨血症的204例临床资料。结果小儿高氨血症204例(男116例、女88例),其中一过性171例(83.8%)、先天性33例(16.2%);年龄28d至10岁。一过性高氨血症与原发疾病引发的严重脓毒症、心衰和休克等有关,表现为呼吸、循环、神经及消化系统等症状体征,患儿经针对原发病治疗后,血氨均降至正常;先天性高氨血症多有引起尿素循环障碍的遗传代谢病,主要表现为喂养困难、反复呕吐、惊厥和肌张力异常、难以纠正的酸中毒、发育落后、肝肿大、黄疸和肝功能异常等。患儿通过治疗,大多病情稳定、症状缓解。结论多种疾病均可引起高氨血症;对符合筛查条件的患儿,检测血氨动态有重要意义;对血氨持续增高的患儿应进行特殊生化检测(血尿氨基酸和有机酸等),对结果综合分析,对相关遗传代谢病早期诊治。     

串联质谱技术在新生儿遗传代谢性疾病筛查中的应用

目的分析串联质谱技术在新生儿遗传代谢性疾病筛查中的应用效果。方法长春市妇幼保健计划生育服务中心自2016年3月-2017年12月采用串联质谱技术针对长春市区助产机构的新生儿采取氨基酸代谢疾病、脂肪酸代谢疾病及有机酸代谢疾病等遗传代谢性疾病的筛查,分析筛查结果及串联质谱技术筛查疾病情况。结果筛查的10 058例新生儿中,阳性病例35例(0. 35%),其中包括氨基酸代谢疾病21例,脂肪酸氧化障碍14例,有1例患儿确诊为苯丙酮尿症。结论在新生儿实施遗传代谢性疾病筛查时利用串联质谱技术,尽早筛查新生儿机体出现的问题,采取对症治疗处理,能够有效提高人口出生综合质量,因此,串联质谱技术在筛查新生儿遗传代谢性疾病中有重要的应用价值。     

2019—2021年宜宾市新生儿遗传代谢疾病筛查情况分析

目的 分析宜宾市新生儿主要遗传代谢病的发病特点,为该地区新生儿遗传代谢病诊断及干预提供参考。方法 回顾性分析2019—2021年宜宾市新生儿筛查中心应用串联质谱技术对71 572例新生儿遗传代谢病的筛查结果,采用SPSS 25.0软件描述性分析该地区新生儿遗传代谢病的发病特点及随访治疗情况。结果 71 572例新生儿中确诊为新生儿遗传代谢病29例,包括氨基酸代谢病5例、有机酸代谢病5例及脂肪酸氧化代谢病19例,总检出率1/2 468。共确诊10种遗传代谢病,常见病种为原发性肉碱吸收障碍(24.14%)、中链酰基辅酶A脱氢酶缺乏症(24.14%)及苯丙氨酸血症(13.79%)。所有病例在确诊后4～6周内均在宜宾市新生儿筛查中心进行了及时、规范的治疗。随访与定期评估结果显示所有病例均未发生由该病引起的患儿智力以及生长发育障碍。结论 2019—2021年宜宾市新生儿遗传代谢性疾病高于全国总检出率,其中脂肪酸氧化障碍占比相对较高。串联质谱法能有效筛查多种遗传代谢病,对新生儿遗传代谢病的发现、诊断及干预有重要意义,有利于提高人口质量。     

承德市新生儿苯丙酮尿症筛查结果分析

苯丙酮尿症（phenylketonuria，PKU）是由于苯丙氨酸（phenylalanine，phe）代谢障碍引起的一种先天性代谢缺陷常染色体隐性遗传病。也是目前可治疗的先天性遗传代谢障碍病之一。通过新生儿疾病筛查可以早期发现、早期治疗，避免智力障碍的发生。承德市妇幼保健院新生儿疾病筛查中心自2002年12月-2005年12月对20882例新生儿进行筛查，确诊苯丙酮尿症患儿5例，报告如下。     

海南省某医院337例NICU患儿串联质谱结果分析

目的探讨串联质谱法对NICU酸碱失衡住院患儿的检测价值,为NICU酸碱失衡患儿遗传代谢病的诊治提供依据。方法采用串联质谱技术,使用PE公司生产的非衍生化多种氨基酸、肉碱和琥珀酰丙酮测定试剂盒(串联质谱法)对海南省妇幼保健院新生儿科337例住院患儿展开氨基酸谱与肉碱谱分析,血串联质谱异常者送血样本至北京迈基诺基因公司做基因诊断,送尿样本至广州金域检验做尿气相质谱验证。结果337例住院患儿中血串联质谱检测到指标异常44例,其中疑似氨基酸血症12例,疑似有机酸血症18例,疑似脂肪酸血症14例,初筛IEM的患病率为13.1%(44/337)。目前已确诊1例同型半胱氨酸血症、2例苯丙酮尿症、1例高苯丙氨酸血症、1例甲基丙二酸血症、1例戊二酸血症I型、1例全羟化酶合成酶缺乏症、2例原发肉碱缺乏症。结论用串联质谱技术可以分析患儿的氨基酸谱与肉碱谱,为NICU酸碱失衡患儿遗传代谢病的诊治提供了依据。     

串联质谱和气相色谱技术在新疆地区高危儿遗传代谢病临床筛查诊断中的应用研究

目的应用串联质谱和气相色谱技术对新疆地区高危儿遗传代谢病结果进行分析,了解该地区遗传代谢病的发病率、临床特点,为临床医师提供诊疗依据。方法选取2014年1月-2019年4月该院临床上高度怀疑遗传代谢病的高危儿2500例为研究对象,应用气相色谱和串联质谱方法进行血液和尿液分析。结果2500例患儿中检测出219阳性病例(阳性率为8.76%),其中男119例,女100例。新生儿期发病80例(36.53%),<1岁84例(38.36%),1~12岁55例(25.11%),并且通过检测发现氨基酸、有机酸及脂肪酸氧化代谢病共18项病种。其中各种氨基酸水平高118例(53.88%),各种有机酸水平高84例(38.36%),各种脂肪酸氧化缺陷病17例(7.76%)。结论临床上通过临床表现及各种实验室检查不能明确病因的疑似遗传代谢病的高危患儿应用串联质谱和气相色谱技术进行筛查可及时发现遗传代谢病患儿,从而得到早期诊断及治疗,降低死亡率、致残率,减轻家庭负担,提高优生优育率,值得临床推广应用。     

Screening for metabolic disorders among high risk infants and children.

In a screening program in Cincinnati urine specimens from over 20,000 infants and children were tested for inherited metabolic disorders involving amino acids, carbohydrates, phenolic acids, organic acids, keto acids, mucopolysaccharides, and imidazoles. The subjects were selected on the basis of symptoms such as vomiting, diarrhea, acidosis, seizures, failure to thrive, delayed development, mental retardation, and others. The tests were based primarily on paper chromatographic techniques. Patients with 21 different metabolic disorders were found. The patterns of abnormal excretion of amino acids and other metabolites are often useful in making a diagnosis.     

非衍生化串联质谱技术分析0~2岁儿童死亡与先天性遗传代谢性疾病的关系

目的 探讨先天性遗传代谢性疾病与0~2岁儿童死亡的关系和串联质谱技术筛查先天性遗传代谢性疾病的可行性。方法 对170例北京市2011年和2012年死亡的0~2岁儿童用串联质谱技术检测其新生儿期采集的滤纸干血片中11种氨基酸代谢指标和13种脂肪酸指标水平,将170例分为0~3、4~6、7~12、13~24月四组,分析每组的儿童死亡人数、出生体重、母亲孕周与氨基酸代谢水平和脂肪酸代谢水平及有机酸代谢障碍之间的关系。结果 170例死亡儿童中有氨基酸代谢指标异常5例,脂肪酸代谢指标异常7例,有机酸代谢障碍4例,共16例,占分析死亡人数的9.4%。0~3月组死亡108例,异常9例,占异常总数的56.25%(9/16);4~6月组死亡26例,异常4例,占异常总数的25.0%(4/16);7~12月组死亡26例,异常3例,占异常总数的18.75%(3/16);13~24月组死亡10例,异常0例。结论 先天性遗传代谢性疾病是造成儿童死亡的原因之一,快速、灵敏、特异的串联质谱技术是早期评价先天性遗传代谢性产物异常的有效方法。     

串联质谱技术在柳州地区高危儿的应用价值

目的 运用串联质谱技术(MS/MS)检测柳州地区临床高危儿氨基酸及酰基肉碱水平,了解本地区临床高危患儿群体遗传代谢疾病的发生情况。方法 选取2013年1月-2015年12月本院住院及门诊高危患儿共2 215例,串联质谱分别检测其氨基酸及肉碱水平。初筛阳性患儿结合临床表型,进一步经不同确诊手段检测分析后,确定确诊病例,并进行随访治疗。结果 在2 215例高危儿的检测结果中,初筛阳性为195例,占8.80%;确诊例数为30例为1.35%。确诊遗传代谢病14种共计30例患儿,其中疾病种类以肉碱缺乏症、希特林蛋白血症、戊二酸血症Ⅰ型为主,其余类型病种均有出现。结论 在广西柳州地区高危儿群体,遗传代谢疾病的比例及病种均有一定发生率,在高危儿遗传代谢疾病的诊疗过程中,运用串联质谱技术可以针对该群体进行早期筛查与疾病预防。     

Protein turnover, ureagenesis and gluconeogenesis

The major processes discussed below are protein turnover (degradation and synthesis), degradation into urea, or conversion into glucose (gluconeogenesis, Figure 1). Daily protein turnover is a dynamic process characterized by a double flux of amino acids: the amino acids released by endogenous (body) protein breakdown can be reutilized and reconverted to protein synthesis, with very little loss. Daily rates of protein turnover in humans (300 to 400 g per day) are largely in excess of the level of protein intake (50 to 80 g per day). A fast growing rate, as in premature babies or in children recovering from malnutrition, leads to a high protein turnover rate and a high protein and energy requirement. Protein metabolism (synthesis and breakdown) is an energy-requiring process, dependent upon endogenous ATP supply. The contribution made by whole-body protein turnover to the resting metabolic rate is important: it represents about 20 % in adults and more in growing children. Metabolism of proteins cannot be disconnected from that of energy since energy balance influences net protein utilization, and since protein intake has an important effect on postprandial thermogenesis - more important than that of fats or carbohydrates. The metabolic need for amino acids is essentially to maintain stores of endogenous tissue proteins within an appropriate range, allowing protein homeostasis to be maintained. Thanks to a dynamic, free amino acid pool, this demand for amino acids can be continuously supplied. The size of the free amino acid pool remains limited and is regulated within narrow limits. The supply of amino acids to cover physiological needs can be derived from 3 sources: 1. Exogenous proteins that release amino acids after digestion and absorption 2. Tissue protein breakdown during protein turnover 3. De novo synthesis, including amino acids (as well as ammonia) derived from the process of urea salvage, following hydrolysis and microflora metabolism in the hind gut. When protein intake surpasses the physiological needs of amino acids, the excess amino acids are disposed of by three major processes: 1. Increased oxidation, with terminal end products such as CO? and ammonia 2. Enhanced ureagenesis i. e. synthesis of urea linked to protein oxidation eliminates the nitrogen radical 3. Gluconeogenesis, i. e. de novo synthesis of glucose. Most of the amino groups of the excess amino acids are converted into urea through the urea cycle, whereas their carbon skeletons are transformed into other intermediates, mostly glucose. This is one of the mechanisms, essential for life, developed by the body to maintain blood glucose within a narrow range, (i. e. glucose homeostasis). It includes the process of gluconeogenesis, i. e. de novo synthesis of glucose from non-glycogenic precursors; in particular certain specific amino acids (for example, alanine), as well as glycerol (derived from fat breakdown) and lactate (derived from muscles). The gluconeogenetic pathway progressively takes over when the supply of glucose from exogenous or endogenous sources (glycogenolysis) becomes insufficient. This process becomes vital during periods of metabolic stress, such as starvation.     

Management of a Woman With Maple Syrup Urine Disease During Pregnancy,Delivery, and Lactation

Maple syrup urine disease (MSUD) is an inherited disorder of metabolism of the branched‐chain amino acids leucine, isoleucine, and valine. Complications of acute elevation in plasma leucine include ketoacidosis and risk of cerebral edema, which can be fatal. Individuals with MSUD are at risk of metabolic crisis throughout life, especially at times of physiological stress. We present a case of successful management of a woman with MSUD through pregnancy, delivery, postpartum, and lactation, including nutrition therapy using modified parenteral nutrition.     

Conditional deficiencies of ornithine or arginine.

Relative deficiencies of ornithine or arginine occur in the presence of excessive ammonia, excessive lysine, growth, pregnancy, trauma, or protein deficiency and malnutrition. Ammonia excess may occur in the presence of a normal liver when amino acid mixtures lacking ornithine, arginine, or citrulline are infused; when specific amino acids such as glycine are injected; when ammonium salts, urea, or urease are injected; or when the gastrointestinal tract contains an excess of protein, urea, or NH4+, as occurs after a gastrointestinal hemorrhage. In these states, ornithine is often rate-limiting for urea cycle function. Ornithine is also rate-limiting when ammonia excess occurs in the presence of hepatic failure. In three of the inherited urea cycle disorders, ornithine insufficiency and ammonia excess also occur. These disorders are citrullinemia, argininosuccinic aciduria, and argininemia. In the presence of excessive lysine the availability of arginine is reduced and the formation of ornithine is decreased in the liver; urea synthesis is reduced, but orotic acid synthesis is increased, and orotic aciduria results as carbamyl phosphate is directed toward the pyrimidine pathway. Hereditary lysinuric protein intolerance results in ornithine depletion, hyperammonemia, and orotic acid uria. Optimal growth in several species of animals requires 0.4-1.0% arginine in the diet. Diets deficient in arginine are associated with poor wound healing as well as stunted growth. The measurement of orotic acid excretion has been a convenient indicator of insufficiency of ornithine or arginine during growth or pregnancy in animals and should prove useful in assessing the requirement for arginine after trauma. Normal human pregnancy is associated with low-grade orotic aciduria. Protein deficiency and malnutrition increase the vulnerability of the animal or child to ammonia toxicity. This is presumably due to insufficient ornithine for normal urea cycle responsiveness.     

Conditional deficiencies of ornithine or arginine

Relative deficiencies of ornithine or arginine occur in the presence of excessive ammonia, excessive lysine, growth, pregnancy, trauma, or protein deficiency and malnutrition. Ammonia excess may occur in the presence of a normal liver when amino acid mixtures lacking ornithine, arginine, or citrulline are infused; when specific amino acids such as glycine are injected; when ammonium salts, urea, or urease are injected; or when the gastrointestinal tract contains an excess of protein, urea, or NH4+, as occurs after a gastrointestinal hemorrhage. In these states, ornithine is often rate-limiting for urea cycle function. Ornithine is also rate-limiting when ammonia excess occurs in the presence of hepatic failure. In three of the inherited urea cycle disorders, ornithine insufficiency and ammonia excess also occur. These disorders are citrullinemia, argininosuccinic aciduria, and argininemia. In the presence of excessive lysine the availability of arginine is reduced and the formation of ornithine is decreased in the liver; urea synthesis is reduced, but orotic acid synthesis is increased, and orotic aciduria results as carbamyl phosphate is directed toward the pyrimidine pathway. Hereditary lysinuric protein intolerance results in ornithine depletion, hyperammonemia, and orotic acid uria. Optimal growth in several species of animals requires 0.4-1.0% arginine in the diet. Diets deficient in arginine are associated with poor wound healing as well as stunted growth. The measurement of orotic acid excretion has been a convenient indicator of insufficiency of ornithine or arginine during growth or pregnancy in animals and should prove useful in assessing the requirement for arginine after trauma. Normal human pregnancy is associated with low-grade orotic aciduria. Protein deficiency and malnutrition increase the vulnerability of the animal or child to ammonia toxicity. This is presumably due to insufficient ornithine for normal urea cycle responsiveness.     

Prolonged exercise testing in two children with a mild Multiple Acyl-CoA-Dehydrogenase deficiency

BACKGROUND: Multiple Acyl-CoA-Dehydrogenase deficiency (MADD) is an inherited metabolic disorder characterized by impaired oxidation of fatty acids and some amino acids. METHODS: We were interested whether children with MADD could tolerate a prolonged low-intensity exercise test and if this test could have any additional diagnostic value. Therefore, we performed a maximal exercise test and a low-intensity prolonged exercise test in 2 patients with MADD and in 5 control subjects. During a prolonged exercise test the subjects exercised on a cycle ergometer at a constant workload of 30% of their maximum for 90 minutes and heart rate, oxygen uptake, fuel utilization and changes in relevant blood and urinary parameters were monitored. RESULTS: The tests were tolerated well. During the prolonged exercise test the fatty acid oxidation (FAO) was quite low compared to 5 control subjects, while characteristic metabolites of MADD appeared in plasma and urine. CONCLUSION: We suggest that the prolonged exercise test could be of diagnostic importance and might replace the fasting test as a diagnostic procedure in some cases, particularly in patients with anamnestic signs of intolerance for prolonged exercise.