Application value of C14∶1/C12∶1 for very long chain acyl-CoA dehydrogenase deficiency in newborn screening / 中华检验医学杂志

Objective:To establish the cut-off value of tetradecenoyl carnitine (C14∶1)/dodecenoyl carnitine(C12∶1) based on non-derivatized tandem mass spectrometry (MS/MS), and to explore the application value of C14∶1/C12∶1 to screen newborns for very long chain acyl-CoA dehydrogenase deficiency (VLCADD), determining the best combination of indicators for screening VLCADD.Methods:This retrospective study included data from 17 newborns with VLCADD detected by MS/MS and confirmed by acyl-CoA dehydrogenase very long chain ( ACADVL) gene detection, and 423 507 newborns with normal MS/MS results. The data from these newborns were collected from January 2014 to December 2021 as the newborns received neonatal screening in Nanjing Neonatal Disease Screening Center and Suzhou Neonatal Disease Screening Center. All newborns were divided into 3 groups: all newborns group, full-term newborns group and normal-birth-weight newborns group, and the cut-off values of C14∶1/C12∶1 for VLCADD in these 3 groups were determined by their receiver operating characteristic (ROC) curves individually. With these results, a total of 5 interpretation schemes were composed using different indicators alone or jointly: scheme 1 being C14∶1/C12∶1, scheme 2 being C14∶1, scheme 3 being C14∶1+C14∶1/C2+C14∶1/C16, scheme 4 being C14∶1/C12∶1+C14∶1, and scheme 5 being C14∶1/C12∶1+C14∶1+C14∶1/C2+C14∶1/C16. The detection rate, false-positive rate and positive predictive value of each scheme were calculated, and their screening efficiencies were statistically compared by Chi-square tests. Results:The cut-off values of C14∶1/C12∶1 for VLCADD in the 3 newborn groups were all 2.80. The detection rates of VLCADD with all 5 interpretation schemes were 17/17. Scheme 1 had the highest false positive rate [26.15‰ (11 075/423 524)] and the lowest positive predictive value [0.15% (17/11 092)]. Scheme 4 (Scheme 5) had the lowest false positive rate [0.02‰ (10/423 524)] and the highest positive predictive value [62.96% (17/27)]. Comparing scheme 4 (Scheme 5) with scheme 1, scheme 2 and scheme 3, the differences of false positive rate (χ2=302.30,11 191.50,32.06) and positive predictive value (χ2=102.51,3 485.61,13.83) were statistically significant (all P<0.001). Conclusion:C14∶1/C12∶1 was an effective auxiliary interpretive indicator for VLCADD in newborn screening, and the combination of C14∶1/C12∶1+C14∶1 was tested to be the best indicator for VLCADD screening based on non-derivatized tandem mass spectrometry.

Consensus on diagnosis and treatment of very long-chain acyl-CoA dehydrogenase deficiency / 浙江大学学报·医学版

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is a metabolic disease of long chain fatty acid oxidation. The clinical manifestations are heterogeneous, mainly with heart, liver, skeletal muscle and brain damage, and the onset of which can be from newborn to adult. Cardiomyopathy type is more serious with high mortality. The liver failure type and myopathy type would be potentially lethal, but generally the prognosis is relatively good. Recurrent hypoglycemia, energy metabolism disorder, liver dysfunction, cardiomyopathy and serious arrhythmia are the main causes of death. Most patients can be identified through neonatal screening, and the prognosis is usually good in patients with early diagnosis and treatment. The purpose of this consensus is to standardize the diagnosis, treatment and management of VLCAD deficiency, so as to improve the prognosis of patients and reduce death and disability.

Newborn screening, gene variation analysis and follow-up study of very long chain acyl CoA dehydrogenase deficiency / 中华实用儿科临床杂志

Objective:To investigate the prevalence, gene variation and prognosis of very long chain acyl CoA dehydrogenase deficiency (VLCADD) in newborns in Henan Province.Methods:From January 2013 to December 2019, 867 103 newborns were investigated for VLCADD by tandem mass spectrometry.Children who diagnosed as VLCADD and their families were subjected to next-generation sequencing and Sanger sequencing.Clinical data, biochemical changes and gene variation characteristics of the confirmed cases of VLCADD were analyzed.Dietary guidance was given, and their growth and development were followed up.Results:Six neonates were diagnosed as VLCADD, and the prevalence of VLCADD in the Henan Province was 1/144 517.A total of 11 mutations in the ACADVL gene were found, including 5 new variants c. 692-2_692-1delAG, c.753-23_753-22del, c.960delG, c.1361A>G, and c. 1955C>T.The newborns were given a high-carbohydrate, low-fat diet, and followed up for 8-56 months.Except for two deaths, all patients had a good outcome. Conclusions:The prevalence of neonatal VLCADD in Henan Province is 1/144 517.This results has enriched the ACADVL gene mutation spectrum and provided an important basis for the screening and diagnosis of VLCADD.

Novel ACADVL variants resulting in mitochondrial defects in long-chain acyl-CoA dehydrogenase deficiency / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The pathogenesis of very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is highly heterogeneous and still unclear. Additional novel variants have been recently detected in the population. The molecular and cellular effects of these previously unreported variants are still poorly understood and require further characterization. To address this problem, we have evaluated the various functions and biochemical consequences of six novel missense variants that lead to mild VLCAD deficiency. Marked deficiencies in fatty acid oxidation (FAO) and other mitochondrial defects were observed in cells carrying one of these six variants (c.541C>T, c.863T>G, c.895A>G, c.1238T>C, c.1276G>A, and c.1505T>A), including reductions in mitochondrial respiratory-chain function and adenosine triphosphate (ATP) production, and increased levels of mitochondrial reactive oxygen species (ROS). Intriguingly, higher apoptosis levels were found in cells carrying the mutant VLCAD under glucose-limited stress. Moreover, the stability of the mutant homodimer was disturbed, and major conformational changes in each mutant VLCAD structure were predicted by molecular dynamics (MD) simulation. The data presented here may provide valuable information for improving management of diagnosis and treatment of VLCAD deficiency and for a better understanding of the general molecular bases of disease variability.

Novel ACADVL variants resulting in mitochondrial defects in long-chain acyl-CoA dehydrogenase deficiency / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The pathogenesis of very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is highly heterogeneous and still unclear. Additional novel variants have been recently detected in the population. The molecular and cellular effects of these previously unreported variants are still poorly understood and require further characterization. To address this problem, we have evaluated the various functions and biochemical consequences of six novel missense variants that lead to mild VLCAD deficiency. Marked deficiencies in fatty acid oxidation (FAO) and other mitochondrial defects were observed in cells carrying one of these six variants (c.541C>T, c.863T>G, c.895A>G, c.1238T>C, c.1276G>A, and c.1505T>A), including reductions in mitochondrial respiratory-chain function and adenosine triphosphate (ATP) production, and increased levels of mitochondrial reactive oxygen species (ROS). Intriguingly, higher apoptosis levels were found in cells carrying the mutant VLCAD under glucose-limited stress. Moreover, the stability of the mutant homodimer was disturbed, and major conformational changes in each mutant VLCAD structure were predicted by molecular dynamics (MD) simulation. The data presented here may provide valuable information for improving management of diagnosis and treatment of VLCAD deficiency and for a better understanding of the general molecular bases of disease variability.

New mutation of ACADVL-related very long chain acyl-CoA dehydrogenase deficiency / 中华实用儿科临床杂志

Objective According to the clinical and gene mutation characteristics of ACADVL-related very long chain acyl-CoA dehydrogenase deficiency(VLCADD),the types that contribute to the gene mutation of ACADVL were summarized.Methods By analyzing clinical,laboratory and genetic data of 1 case with ACADVL-related very long chain acyl-CoA dehydrogenase deficiency diagnosed from Department of Pediatrics,the Affiliated Hospital of Inner Mongolia Medical University in August 2016,based on the agreement signed by both the litde patient's parents and the hospital,plus the high-throughput sequencing analysis and PCR sequencing test for the 2 generation genes,some presented mutation sites were analyzed and concluded,in addition to taking "ACADVL" as key words to search the databases from CNKI,Wanfang(updated in 2016) as well as PubMed and related documents from On-line Mendal Inheritant databases of Man (OMIM) and HGMD.Results Through physical examination,VLCADD was diagnosed.After being given Levocamitine and the diet likemedium-chain fatty acid food for a week,the metabolism returned to normal.Tracking him for 3 months,his hepatitis obviously rebounded,within the reach of 3 cm under the right rib and 1 cm under the xiphoid.The exome sequencing study (trios) was identified the novel heterozygous mutation according to the statistics below A CAD VL (N M_000018.3) Exon7:c.608 C ＞ T;p.(Pro203 Leu) (heterozygous) and A CAD VL (NM _000018.3) Exon18:c.1748C ＞ T;p.(Ser583Leu) (heterozygous) in ACADVL.Relevant literature reported suggest these two mutations from both the parents are pathogenic genes,which can account for the reason why the boy got ill.However,these two mutations had not been reported in ACADVL-related VLCADD so far.Up to now,73 types of mutations from documents index were related to the VLCADD,but the clinical case included 75 kinds of gene mutations.Conclusions The apparent symptoms of the boy with the gene mutation were reflected in abnormal heart rates,hepatomegaly and hypoglycemia.VLCADD was diagnosed through genetic testing,and systematic treatment can partly control the development of the disease.In conclusion,the findings (exon 7 and 18) show that according to the genetic tests,disease-causing genes from both parents are new mutations of ACADVL and they are pathogenic.

Analysis of clinical and genetic results in one case of very long chain acyl-CoA dehydrogenase deficiency / 中华内分泌代谢杂志

Clinical characteristics were analyzed in a child with very long chain acyl-CoA dehydrogenase deficiency( VLCADD) . The gene analysis was performed in 20 exon all coding regions and 10 bp shear zone in the very long chain acyl-CoA dehydrogenase( VLCAD) gene of the case and his family members by direct sequencing of PCR-DNA from peripheral blood. The results showed that the patient presented with acute onset, clinical manifestations of repeated vomiting, poor spirit, abnormal liver function, increased myocardial enzyme kinase. At the age of one year old, this child was diagnosed with Reye's syndrome for liver injury. Genetic testing results revealed that E14 c. 1349G>A, p. R450H heterozygous mutation in VLCAD gene was found in this case, his mother, and his younger sister, and E15 c. 1532G>A, p. R511Q heterozygous mutation was found in this case and his father. The pathogenic genes of the case are from his mother and the younger sister is a carrier.

Very long chain acyl-CoA dehydrogenase deficiency：a case report with literature review / 临床儿科杂志

Objective To explore the clinical features of very long chain acyl-CoA dehydrogenase deifciency (VLCADD). Methods The clinical manifestation and the biochemical data of one baby girl with VLCADD were summarized and related literatures were reviewed. Results Female patient, aged 7 months, presented with recurrent vomit, haematemesis, stare, nodal tachycardia, hypoglycemia, abnormal liver function and myocardial enzyme. She died after one month due to frequent relapse together with withdrawing treatment. Conclusion VLCADD as a rare disease that cause sudden unexpected death in infant, the early diagnosis and treatment are important to patients.

Implementación diagnóstica de la deficiencia de acil-CoA deshidrogenasa de cadena muy larga / Diagnostic implementation of very long chain acyl-CoA dehydrogenase deficiency / Implementação diagnóstica da deficiência de acil-CoA desidrogenase de cadeia muito longa

La enzima acil-CoA deshidrogenasa de cadena muy larga (VLCAD) es un homodímero que cataliza la reacción inicial de la ß-oxidación mitocondrial de los ácidos grasos. El presente estudio tuvo como objetivo el análisis de los metabolitos producidos por fibroblastos incubados en presencia de sustratos tritiados vs. deuterados, como herramienta diagnóstica de la deficiencia de VLCAD. Fue encontrada severamente deprimida la oxidación de los sustratos tritiados en los fibroblastos de pacientes con esta enfermedad, asimismo la incubación con sustratos deuterados aportó un perfil característico en esta deficiencia. El método de valoración de agua tritiada, aunque inespecífico, debido a que la oxidación de sustratos tritiados también puede estar deprimida en otras deficiencias, es un buen método para sugerir una deficiencia de acil- CoA deshidrogenasa de cadena muy larga, si el análisis se compara con otros hallazgos propios de la deficiencia enzimática. Sin embargo, la determinación de los metabolitos deuterados es más específica, por encontrarse un perfil característico que muestra niveles elevados de los ácidos grasos octanoico, decanoico, dodecenoico, dodecanoico, tetradecenoico, tetradecanoico y hexadecenoico, lo que la hace diferente de otras deficiencias enzimáticas.

Very long-chain acyl-CoA dehydrogenase (VLCAD) is a homodimer that catalyzes the initial reaction of fatty acid ß-oxidation. The objective of the present study was to analyse the metabolites produced by fibroblasts incubated with tritiated vs. deuterated substrates, as a diagnostic tool for the diagnosis of VLCAD deficiency. A severe depression for oxidizing the tritiated substrates was observed for these patients' fibroblasts, and a characteristic profile for this deficiency was found when incubating fibroblasts with deuterated substrates. The method which evaluates the production of tritiated water is nonspecific as the oxidation of tritiated substrates can be found depressed in other fatty acid ß-oxidation disorders; however this method can suggest VLCAD deficiency if the tritiated water measurement is compared with others findings related to this deficiency. On the other hand the measurement of deuterated metabolites is more specific as a characteristic profile was found for this deficiency showing increased levels of the following organic acids: octanoic, decanoic, dodecenoic, dodecanoic, tetradecenoic, tetradecanoic and hexadecanoic, which is different from other fatty acid ß-oxidation disorders.

A enzima acil-CoA desidrogenase de cadeia muito longa (VLCAD) é um homodímero que catalisa a reação inicial da ß-oxidação mitocondrial dos ácidos graxos. O presente estudo teve como objetivo a análise dos metabólitos produzidos por Ibroblastos incubados em presença de substratos tritiados vs. deuterados, como ferramenta de diagnóstico da deIciência de VLCAD. Foi encontrada severamente deprimida a oxidação dos substratos tritiados nos Ibroblastos de pacientes com esta doença, do mesmo modo a incubação com substratos deuterados deu um perIl característico nesta deIciência. O método de avaliação de água tritiada, embora não especíIco, devido a que a oxidação de substratos tritiados também pode estar deprimida em outras deIciências, é um bom método para sugerir uma deIciência de acil-CoA desidrogenase de cadeia muito longa, se a análise é comparada com outros achados próprios da deIciência enzimática. Entretanto, a determinação dos metabólitos deuterados é mais especiIca, devido a que se encontra um perIl característico que mostra níveis elevados dos ácidos graxos octanoico, decanoico, dodecenoico, dodecanoico, tetradecenoico, tetradecanoico e hexadecenoico, o que a torna diferente de outras deIciências enzimáticas.

MCT oil-based diet reverses hypertrophic cardiomyopathy in a patient with very long chain acyl-coA dehydrogenase deficiency.

Very long chain acyl-CoA dehydrogenase (VLCAD) deficiency is one of the genetic defects of mitochondrial fatty acid beta-oxidation presenting in early infancy or childhood. If undiagnosed and untreated, VLCAD deficiency may be fatal, secondary to cardiac involvement. We assessed the effect of replacing part of the fat in the diet of a 2 ½-month-old male infant, who was diagnosed with VLCAD deficiency,with medium-chain triglyceride (MCT) oil and essential fats. The patient presented with vomiting, dehydration, and was found to have persistent elevation of liver function tests, hepatomegaly, pericardial and pleural effusion, right bundle branch block, and biventricular hypertrophy. Because of the cardiomyopathy, hepatomegaly, and an abnormal acylcarnitine profile and urine organic acids, he was suspected of having VLCAD deficiency. This was confirmed on acyl-coA dehydrogenase, very long chain (ACADVL) gene analysis. He was begun on an MCT oil-based formula with added essential fatty acids, uncooked cornstarch (around 1 year of age), and frequent feeds. By 7 months of age, cardiomyopathy had reversed and by 18 months of age, all cardiac medications were discontinued and hypotonia had improved such that physical therapy was no longer required. At 5 years of age, he is at the 50th percentile for height and weight along with normal development. Pediatricians need to be aware about the basic pathophysiology of the disease and the rationale behind its treatment as more patients are being diagnosed because of expansion of newborn screen. The use of MCT oil as a medical intervention for treatment of VLCAD deficiency remains controversial mostly because of lack of clear phenotype-genotype correlations, secondary to the genetic heterogeneity of the mutations. Our case demonstrated the medical necessity of MCT oil-based nutritional intervention and the need for the further research for the development of specific guidelines to improve the care of these patients.

Progress in the very long chain acyl - CoA dehydrogenase deficiency / 国际儿科学杂志

Very long chain acyl - CoA dehydrogenase deficiency (VLCADD) is a rare recessively inherited disorder of mitochondrial fatty acid β - oxidation. VLCADD is classfied into three types according the onset age and clinical manifestation: cardiomyopathic phenotype, hepatic phenotype and myopathic phenotype. The cardiomyopathic phenotype is most severe resulting in high mortality. The biochemical hallmark of the disease is elevation of C14:1 -camitine detected by tandem mass spectrometry .Enzyme analysis, molecular genetic analysis and fatty acid oxidation flux assay are used to make further diagnostic evaluation. Treatment regimens include avoidance of fasting, restriction of long - chain fat acid and supplementation of medium - chain triglycerides.