极长链酰基辅酶A脱氢酶缺乏症研究进展

极长链酰基辅酶A脱氢酶缺乏症是一种较罕见的脂肪酸代谢障碍疾病,根据起病年龄和临床表现分为三型：心肌病型、肝型、肌病型。心肌病型病情重,病死率高。临床诊断可通过血串联质谱(MS/MS)检测血肉豆蔻烯酰基肉碱(C14:1)水平进行,进一步确诊可通过基因诊断、酶学分析及脂肪酸氧化流量分析。治疗上主要包括避免空腹,减少长链脂肪酸的摄入,补充中链甘油三酯等。     

Milder childhood form of very long-chain acyl-CoA dehydrogenase deficiency in a 6-year-old Japanese boy

We investigated the clinical and biochemical characteristics of a 6-year-old Japanese boy with very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency. He had hypoketotic hypoglycaemia, exercise- and fasting-induced lethargy, hepatomegaly and cardiomegaly. Significant laboratory findings included elevated plasma levels of creatine phosphokinase and acyl-carnitine and a fatty liver at biopsy suggesting a diagnosis of VLCAD deficiency. Conclusion The diagnosis of very long-chain acyl-CoA dehydrogenase deficiency was supported by the results of acyl-CoA dehydrogenase activity for C₈ and C₁₆ fatty acids in skin fibroblasts from the patient. Treatment with medium chain triglycerides and l-carnitine in the diet improved his hepatomegaly and cardiomegaly. Received: 17 April 2000 / Accepted: 5 July 2000     

MS/MS-based newborn and family screening detects asymptomatic patients with very-long-chain acyl-CoA dehydrogenase deficiency

OBJECTIVES: To determine whether asymptomatic persons with biochemical evidence of very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency identified through expanded newborn screening with tandem mass spectometry have confirmed disease. STUDY DESIGN: We characterized 8 asymptomatic VLCAD-deficient individuals by enzyme and/or mutational analysis and compared them with clinically diagnosed, symptomatic patients with regard to mutations, enzyme activity, phenotype, and age of disease onset. RESULTS: VLCAD molecular analyses in 6 unrelated patients revealed the previously reported V243A mutation, associated with hepatic or myopathic phenotypes, on 7/12 alleles. All other mutations were also missense mutations. Residual VLCAD activities of 6% to 11% of normal were consistent with milder phenotypes. In these identified individuals treated prospectively with dietary modification as preventive measures, clinical symptoms did not develop during follow-up. CONCLUSIONS: MS/MS-based newborn screening correctly identifies VLCAD-deficient individuals. Based on mutational and enzymatic findings, these infants probably are at risk of future disease. Because life-threatening metabolic derangement can occur even in otherwise mild phenotypes, we advocate universal newborn screening programs for VLCAD deficiency to detect affected patients and prevent development of metabolic crises. Longer-term follow-up is essential to define outcomes, the definite risk of future disease, and appropriate treatment recommendations.     

Positive newborn screen in a normal infant of a mother with asymptomatic very long-chain Acyl-CoA dehydrogenase deficiency

A neonate with elevated tetradecenoylcarnitine (C14:1) on the newborn screen was evaluated for possible very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) and found to be a carrier. However, his symptom-free mother was subsequently diagnosed with VLCADD. This documents maternal VLCADD causing a positive newborn screening result in an offspring.     

Pitfalls of neonatal screening for very-long-chain acyl-CoA dehydrogenase deficiency using tandem mass spectrometry

Neonatal screening programs for very-long-chain acyl-CoA dehydrogenase deficiency (VLCADD) have recently been implemented. We report 2 newborns with elevated C14:1-carnitine levels on day 3 of life and normal levels on days 5 to 7. Enzyme and molecular analyses confirmed VLCADD in the first patient and heterozygosity in the second patient. We conclude that the diagnosis of VLCADD can be missed by acylcarnitine analysis during anabolic conditions. An increased C14:1-carnitine level can also occur in heterozygous individuals. Elevated C14:1-carnitine level on neonatal screening warrants further diagnostic workup even if a repeat sample demonstrates normal acylcarnitine levels.     

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

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）3.52 μmol/L（参考值0.02~0.2 μmol/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）1.66 μmol/L（参考值0.06~0.6 μmol/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。     

短链酰基辅酶A 脱氢酶缺乏症患儿临床特点及基因变异分析

目的探讨新生儿短链酰基辅酶A脱氢酶缺乏症(SCADD)基因型与表型的关系。方法回顾分析2015年至2018年,在青岛地区296 627例新生儿中筛查发现的7例SCADD患儿的临床资料。结果研究期间初次筛查可疑阳性人数为4 864例,初筛阳性率为0.16%;经基因检测确诊7例SCADD患儿,确诊阳性率为1/42375。7例患儿中,男性4例、女性3例,基因检测发现5种已知变异、4种未知变异,分别为c.1029+89_90insC、c.1031AG、c.1157GA、c.164CT和c.989GA,c.1130CT、c.1186GA、c.445AT和c.949AG。结论 SCADD基因型与血尿串联质谱筛查结果一致,但与临床表型关系不明确,早期诊断和治疗有助改善预后。     

Medium-chain acyl-CoA dehydrogenase deficiency does not correlate with apparent life-threatening events and the sudden infant death syndrome: results from phenylpropionate loading tests and DNA analysis

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most common inherited disorder of fatty acid metabolism and typically presents in early childhood as potentially fatal hypoketotic, hypoglycaemic crisis often associated with Reye-like symptoms. Re-investigations of cases of sudden infant death syndrome (SIDS) have revealed in some instances a deficiency of MCAD, suggesting that this metabolic disorder may lead to sudden infant death without prior clinical symptoms. In the present study, we examined 142 infants who had suffered from an apparent life-threatening event (ALTE) or were otherwise considered at risk for SIDS for MCAD deficiency by phenylpropionate loading. In no case excretion of phenylpropionylglycine, the hallmark of MCAD deficiency, was increased. In contrast, 3 out of 55 children with symptoms of metabolic disorders showed increased phenylpropionylglycine excretion, and in all three cases MCAD deficiency was confirmed by DNA analysis. In addition, we investigated 142 cases of sudden unexplained child death and 100 control subjects for the A985G mutation in the MCAD gene which is associated with about 98% of enzyme deficiencies. We found one case of heterozygosity each in the patient and control group. Our data indicate that MCAD deficiency is not a major cause of ALTE and, in agreement with results from similar studies in other countries, its frequency is not increased in children who died of SIDS.     

Adrenal insufficiency in asymptomatic adrenoleukodystrophy patients identified by very long-chain fatty acid screening

OBJECTIVE: Plasma assay for very long-chain fatty acids has made it possible to perform large-scale screening of at-risk individuals to identify asymptomatic patients with X-linked adrenoleukodystrophy (X-ALD). We evaluated the burden of undiagnosed adrenal insufficiency in 49 such patients (age, 4.5 +/- 3.5 years). STUDY DESIGN: Serum adrenocorticotropic hormone (ACTH) and standard-dose ACTH stimulation test were performed at the baseline and followed prospectively until initiation of adrenal replacement therapy (follow-up, 2 +/- 1.7 years). RESULTS: At baseline, 39 (80%) patients had impaired adrenal function, serum ACTH levels were elevated in 34 (69%) patients, and ACTH stimulation test was abnormal in 21(43%) patients. There was a moderate association between Serum ACTH and age at baseline, ( r = 0.32, P = .05). By the end of follow-up, 86% of patients had borderline or overt adrenal insufficiency (age of onset, 4.8 +/- 3.7 years). CONCLUSIONS: We detected a high prevalence of unrecognized adrenocortical insufficiency in asymptomatic boys with X-ALD. It is known to be a frequent cause of morbidity and can be prevented by careful monitoring, early identification of impaired adrenal reserve, and timely initiation of therapy. It manifests early and before onset of neurologic symptoms, suggesting X-ALD as a candidate disorder for neonatal screening.     

多种酰基辅酶A脱氢酶缺乏症遗传学研究进展

<正>多种酰基辅酶A脱氢酶缺乏症(multiple acyl-CoA dehydrogenasedeficiency,MADD)是由于线粒体氧化呼吸链脱氢产生的电子传递障碍导致脂肪酸、氨基酸及胆碱代谢障碍的一组临床异质性遗传病^[1]。可通过串联质谱分析血酰基肉碱水平对MADD进行新生儿筛查,不同国家和地区新生儿发病率差异较大,美国发病率为1/378 272,德国发病率为1/195 000,     

Glyceroltrioleate/glyceroltrierucate therapy in 16 patients with X-chromosomal adrenoleukodystrophy/adrenomyeloneuropathy: Effect on clinical,biochemical and neurophysiological parameters

We have investigated the effect of glyceroltrioleate/glyceroltrierucate (GTO/GTE) therapy on X-chromosomal adrenoleukodystrophy in 16 patients with adrenoleukodystrophy (n=6), adrenomyeloneuropathy (n=3), Addison disease without neurological involvement (n=2), and neurologically and endocrinologically asymptomatic patients (n=5). Therapy was carried out for 19.4±10 months. All patients showed a normalization of C 26:0 plasma fatty acid concentrations. None of the seven neurologically asymptomatic patients developed neurological symptoms. Somatosensory evoked potentials of the tibialis nerve was the most sensitive electrophysiological parameter, showing a slight improvement in neurologically asymptomatic patients during therapy. In none of the patients with normal cranial MRI at start of therapy (n=6) has MRI deterioration been observed whilst on therapy. Follow up of the neurologically asymptomatic children supports the hypothesis that GTO/GTE therapy might prevent the development of neurological symptoms. Six of the nine neurologically symptomatic patients deteriorated to varying degrees whilst on therapy. MRI alterations have worsened in all patients with clinical deterioration.Conclusion GTO/GTE treatment should be initiated in all neurological asymptomatic boys before first neurological symptoms develop. To discover these patients very long-chain fatty acid determination should be performed in all family members at risk when adrenoleukodystrophy or adrenomyeloneuropathy is diagnosed.     

中链酰基辅酶A脱氢酶缺乏症诊治进展

中链酰基辅酶A脱氢酶缺乏症是一种较为常见的线粒体脂肪酸氧化缺陷病。临床表现常见低酮性低血糖、呕吐以及嗜睡、肌无力等。临床表现各异及生化检查不典型可增大诊断难度,容易误诊。由于可以导致急性、致命性低血糖和昏迷发作,若未及时诊治,病死率及遗留后遗症的发生率高,行新生儿遗传代谢病筛查早期确诊并及时治疗,可得到较为满意的结果。     

多种酰基辅酶A脱氢酶缺乏症儿童与成人患者临床特点比较

目的比较儿童和成人多种酰基辅酶A脱氢酶缺乏症(MADD)患者的临床和实验室检查特点。方法对12例儿童和19例成人MADD患者进行常规实验室检查、血酰基肉碱谱及尿有机酸分析。对中国人电子转运黄素蛋白脱氢酶(ETFDH)基因常见突变A84T通过DNA测序方法进行筛检。结果儿童MADD患者临床表现高度异质,可表现为肌无力、肝大、低酮性低血糖、肥厚性心肌病或脑发育不良及脱髓鞘病变;而成人患者均以肌无力起病。成人和儿童MADD有肝酶和CK升高,血多种酰基肉碱升高,多数伴有二羧酸尿。儿童组3例死亡,成人组全部存活。存活患者的症状和生化指标治疗后好转或正常。A84T突变在儿童和成人患者的发生率分别为20.8%(5/24)和21%(8/38)。结论儿童与成人MADD患者的临床表现和预后存在差异,成人患者预后好;A84T突变可能与轻型相关。[临床儿科杂志,2012,30(5):446-449]     

Cardiomyopathy in Multiple Acyl-CoA Dehydrogenase Deficiency

Multiple acyl-CoA dehydrogenase deficiency (MADD) is a rare autosomal recessive defect of the electron transfer flavoprotein or ubiquinone oxidoreductase, resulting in abnormal fatty acid, amino acid, and choline metabolism, leading to metabolic acidosis, hypoglycemia, “sweaty-feet” odor, and early neonatal deaths. This report presents a child diagnosed with this disease at birth by newborn screening using the mass spectrometer, who died suddenly at the age of 6 months. The echocardiogram revealed pericardial effusion, thickened ventricular musculature, and insufficiency of both the atrio-ventricular valves. The autopsy showed immense cardiomegaly, fatty infiltration, and hypertrophy of the ventricles. This is the first detailed case report of clinico-pathological correlation of MADD in an infant and brings into light a rare form of cardiomyopathy as a differential diagnosis in critically ill patients.     

A new case of short-chain acyl-CoA dehydrogenase deficiency with isolated ethylmalonic aciduria

A 28-month-old Turkish girl presented with recurrent bronchopneumonia and severe muscular hypotonia. Urinary excretion of ethylmalonic acid was persistently elevated, methylsuccinate appearing only in stress situations. Studies in cultured fibroblasts showed a deficiency of short-chain acyl-CoA dehydrogenase.     

Influence of valproic acid on the expression of various acyl-CoA dehydrogenases in rats

BACKGROUND: Valproic acid (2-propyl-N-pentanoic acid, VPA) causes severe hepatic dysfunction, similar to Reye's syndrome, in a small number of patients. An enhanced excretion of dicarboxylic acids by patients indicates an interference with mitochondrial beta-oxidation. We investigated the expression of various acyl-coenzyme A (acyl-CoA) dehydrogenases (ACD), which catalyze the first step of beta-oxidation in VPA-treated rats. METHODS: The control group received normal saline and the experimental group received VPA (500 mg/kg per day) by intraperitoneal injections for 7 days. Various clinical chemistry parameters in rat blood and free and total carnitine levels in plasma and tissue were determined. Mitochondria were isolated from rat liver and heart and the relative amount of each ACD protein was determined by immunoblot analysis. Total RNA was prepared from various tissues and the mRNA levels for various ACD were measured by slot-blot hybridization analysis using respective cDNA probes. RESULTS: Administration of VPA to rats caused various metabolic effects including hypoglycemia, hyperammonemia and decreased beta-hydroxybutyrate concentration. Free carnitine levels in plasma and heart were also decreased. Enzyme activities of various acyl-CoA dehydrogenases, which are involved in fatty acid oxidation, decreased moderately in heart (57-79%), and slightly in liver (78-95%). The most prominent effects were observed in mRNA levels involved in fatty acid oxidation (short-, medium- and long-chain acyl-CoA dehydrogenase). Each mRNA increased in the liver, kidney, skeletal muscle and heart to varying degrees when rats were fed ad libitum. The increase of short- and medium- chain acyl-CoA dehydrogenase mRNA in the heart were particularly large. However, 3 day starvation strongly inhibited expression of ACD in VPA-treated rats. There was an apparent decrease in the amount of ACD mRNA and proteins in VPA-treated liver. CONCLUSIONS: Valproic acid causes enhanced expression of fatty ACD mRNA, especially in the heart, by a feedback mechanism related to inhibition of beta-oxidation in rats fed ad libitum. However, it impairs the expression of ACD in the liver when there is a drastic change in nutritional state.