RESUMEN
OBJECTIVES: To investigate the clinical and genetic features of children with 3-methylcrotonyl-coenzyme A carboxylase deficiency (MCCD). METHODS: A retrospective analysis was conducted on the clinical manifestations and genetic testing results of six children with MCCD who attended Children's Hospital Affiliated to Zhengzhou University from January 2018 to October 2023. RESULTS: Among the six children with MCCD, there were 4 boys and 2 girls, with a mean age of 7 days at the time of attending the hospital and 45 days at the time of confirmed diagnosis. Of all children, one had abnormal urine odor and five had no clinical symptoms. All six children had increases in blood 3-hydroxyisovaleryl carnitine and urinary 3-hydroxyisovaleric acid and 3-methylcrotonoylglycine, and five of them had a reduction in free carnitine. A total of six mutations were identified in the MCCC1 gene, i.e., c.1630del(p.R544Dfs*2), c.269A>G(p.D90G), c.1609T>A(p.F537I), c.639+2T>A, c.761+1G>T, and c.1331G>A(p.R444H), and three mutations were identified in the MCCC2 gene, i.e., c.838G>T(p.D280Y), c.592C>T(p.Q198*,366), and c.1342G>A(p.G448A). Among these mutations, c.269A>G(p.D90G) and c.1609T>A(p.F537I) had not been previously reported in the literature. There was one case of maternal MCCD, and the child carried a heterozygous mutation from her mother. Five children with a reduction in free carnitine were given supplementation of L-carnitine, and free carnitine was restored to the normal level at the last follow-up visit. CONCLUSIONS: This study identifies two new mutations, c.269A>G(p.D90G) and c.1609T>A(p.F537I), thereby expanding the mutation spectrum of the MCCC1 gene. A combination of blood amino acid and acylcarnitine profiles, urine organic acid analysis, and genetic testing can facilitate early diagnosis and treatment of MCCD, and provide essential data for genetic counseling.
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Carnitina , Mutación , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Ligasas de Carbono-Carbono/genética , Ligasas de Carbono-Carbono/deficiencia , Carboxiliasas/genética , Carboxiliasas/deficiencia , Carnitina/análogos & derivados , Carnitina/sangre , Estudios Retrospectivos , Trastornos Innatos del Ciclo de la Urea/genética , Trastornos Innatos del Ciclo de la Urea/diagnósticoRESUMEN
Identifying multiple ultra-rare genetic syndromes with overlapping phenotypes is a diagnostic conundrum in clinical genetics. This study investigated the pathogenicity of a homozygous missense variant in GNB5 (GNB5L; NM_016194.4: c.920T > G (p. Leu307Arg); GNB5S; NM_006578.4: c.794T > G (p. Leu265Arg)) identified through exome sequencing in a female child who also had 3-methylcrotonyl-CoA carboxylase (3-MCC) deficiency (newborn screening positive) and hemoglobin E trait. The proband presented with early-onset intellectual disability, the severity of which was more in keeping with GNB5-related disorder than 3-MCC deficiency. She later developed bradycardia and cardiac arrest, and upon re-phenotyping showed cone photo-transduction recovery deficit, all known only to GNB5-related disorders. Patient-derived fibroblast assays showed preserved GNB5S expression, but bioluminescence resonance energy transfer assay showed abolished function of the variant reconstituted Gß5S containing RGS complexes for deactivation of D2 dopamine receptor activity, confirming variant pathogenicity. This study highlights the need for precise phenotyping and functional assays to facilitate variant classification and clinical diagnosis in patients with complex medical conditions.
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Ligasas de Carbono-Carbono/genética , Subunidades beta de la Proteína de Unión al GTP/química , Subunidades beta de la Proteína de Unión al GTP/genética , Enfermedades Genéticas Congénitas/diagnóstico , Enfermedades Genéticas Congénitas/etiología , Transferencia de Energía por Resonancia de Bioluminiscencia , Ligasas de Carbono-Carbono/deficiencia , Niño , Oftalmopatías/etiología , Oftalmopatías/genética , Femenino , Subunidades beta de la Proteína de Unión al GTP/metabolismo , Enfermedades Genéticas Congénitas/genética , Variación Genética , Células HEK293 , Humanos , Recién Nacido , Discapacidad Intelectual/genética , Masculino , Tamizaje Neonatal , Fenotipo , Reproducibilidad de los Resultados , Trastornos Innatos del Ciclo de la Urea/etiología , Secuenciación del ExomaRESUMEN
OBJECTIVE: To explore the genetic basis for a child with clinically suspected 3-methylcrotonyl-coenzyme A carboxylase deficiency (MCCD). METHODS: Genomic DNA was extracted from peripheral blood samples of the proband and her parents. Whole exome sequencing was used to screen pathogenic variant in the proband. Suspected variant was verified by Sanger sequencing. Impact of the variant on the structure and function of protein product was analyzed by using bioinformatic software. RESULTS: Sanger sequencing showed that the proband has carried homozygous missense c.1342G>A (p.Gly448Ala) variant of the MCCC2 gene, for which her mother was a heterozygous carrier. The same variant was not detected in her father. The variant was predicted to be pathogenic by PolyPhen-2 and Mutation Taster software, and the site was highly conserved among various species. Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.1342G>A (p.Gly448Ala) variant of MCCC2 gene was predicted to be likely pathogenic(PM2+PP2-PP5). CONCLUSION: The homozygous missense variant of the MCCC2 gene c.1342G>A (p.Gly448Ala) probably underlay the molecular pathogenesis of the proband. Genetic testing has confirmed the clinical diagnosis.
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Ligasas de Carbono-Carbono/deficiencia , Mutación Missense , Trastornos Innatos del Ciclo de la Urea , Ligasas de Carbono-Carbono/genética , Niño , Femenino , Humanos , Masculino , Mutación Missense/genética , Linaje , Trastornos Innatos del Ciclo de la Urea/genéticaRESUMEN
Objective To evaluate whether 3-methylcrotonyl-CoA carboxylase deficiency (3-MCCD) should be routinely screened in newborns. Methods Dried blood spots (DBS) were collected and analyzed by tandem mass spectrometry (TMS). Blood samples were collected from infants with positive 3-MCCD results. Targeted sequencing was performed using the extended panel for inherited metabolic diseases to detect 306 genes. The sequencing libraries were quantified and used for massively parallel sequencing on the Illumina HiSeq 2500 platform. Results A total of 536,008 infants underwent newborn screening (NBS) and 14 cases of 3-MCCD were diagnosed. The incidence of 3-MCCD in Jiangsu province was 1:38,286. During the last 3 years of follow-up, none of the subjects with 3-MCCD exhibited obvious clinical symptoms. Only two children had mild feeding difficulties and vomiting. Eleven patients had complex variants of the MCCC1 gene, and three patients had mutations in MCCC2. In total, 17 types of MCCC1 or MCCC2 variants were found, and c.639 + 2t > a was the most common mutation. Conclusions As far as the current results are concerned, 3-MCCD may be benign in Jiangsu province. However, additional investigations and a longer follow-up period are necessary to decide whether NBS of 3-MCCD is necessary or not.
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Ligasas de Carbono-Carbono/deficiencia , Mutación , Tamizaje Neonatal/métodos , Trastornos Innatos del Ciclo de la Urea/diagnóstico , Ligasas de Carbono-Carbono/genética , Preescolar , China/epidemiología , Pruebas con Sangre Seca , Femenino , Estudios de Seguimiento , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Pronóstico , Medición de Riesgo , Trastornos Innatos del Ciclo de la Urea/epidemiología , Trastornos Innatos del Ciclo de la Urea/genéticaRESUMEN
3-Methylcrotonylglycinuria (3-MCG) is an autosomal recessive inborn error of leucine metabolism caused by the deficiency of 3-methylocrotonyl-CoA carboxylase (3-MCC deficiency). It is the most commonly detected organic aciduria in newborn screening conducted by tandem mass spectrometry (MS/MS) [1, 2]. The clinical phenotype is heterogeneous, ranging from asymptomatic to acute metabolic decompensations [3, 4]. Although at least in severe cases and in acute life threatening episodes limiting natural protein intake (particularly leucine) together with high caloric intake during catabolic periods is required, the need for specific dietary management often seems questionable [2]. In contrast with the 3-MCC deficiency, in diabetes mellitus type 1 (DM1) a diet based on carbohydrate and protein-fat exchangers is beyond dispute. However, as DM1 is quite a common disease, it may occur in a single patient with a rare disease, such as 3-MCC deficiency.
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Ligasas de Carbono-Carbono/deficiencia , Diabetes Mellitus Tipo 1/dietoterapia , Manejo de la Enfermedad , Trastornos Innatos del Ciclo de la Urea/dietoterapia , Preescolar , Diabetes Mellitus Tipo 1/complicaciones , Dieta , Dieta para Diabéticos , Femenino , Humanos , Trastornos Innatos del Ciclo de la Urea/complicacionesRESUMEN
OBJECTIVES: Contrary to many western European countries, most south-eastern European countries do not have an expanded newborn screening (NBS) program using tandem mass spectrometry. This study would represent one of the first expanded NBS studies in south-eastern Europe and will enable the estimation of the incidences of IEM in Slovenia. We proposed an expanded NBS approach including next-generation sequencing (NGS) as a confirmational analysis. DESIGN & METHODS: We conducted a pilot study of expanded NBS for selected inborn errors of metabolism (IEM) in Slovenia including 10,048 NBS cards. We used an approach including tandem mass spectrometry followed by second tier tests including NGS. Based on the NBS results, 85 children were evaluated at a metabolic follow-up; 80 of them were analyzed using NGS. RESULTS: Altogether, glutaric acidemia type 1 was confirmed in one patient who was a compound heterozygote for two known causative GCDH variants. A patient with suspected very long-chain acyl-CoA dehydrogenase deficiency had negative metabolic follow-up tests, but had two heterozygous ACADVL variants; one known disease-causing variant and one indel, namely c.205-8_205-7delinsGC, that is predicted to be causative. Nine participants had elevated metabolites characteristic of 3-methylcrotonyl-CoA carboxylase deficiency, 2 of them had known causative homozygous variants in MCCC1. The other seven were heterozygous; two had a novel genetic variant c.149_151dupCCA (p.Thr50dup). Cumulative incidences of IEM in Slovenia were similar to other European countries. CONCLUSIONS: NGS proved to be valuable in explaining the abnormal metabolite concentrations in NBS as it enabled the differentiation between affected patients and mere heterozygotes, and it improved the turnaround time of genetic analysis. The results of this study will be instrumental in the routine implementation of expanded NBS in Slovenia.
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Errores Innatos del Metabolismo/diagnóstico , Tamizaje Neonatal/métodos , Acil-CoA Deshidrogenasa de Cadena Larga/deficiencia , Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Encefalopatías Metabólicas/diagnóstico , Ligasas de Carbono-Carbono/deficiencia , Síndromes Congénitos de Insuficiencia de la Médula Ósea , Femenino , Estudios de Seguimiento , Glutaril-CoA Deshidrogenasa/deficiencia , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Recién Nacido , Errores Innatos del Metabolismo Lipídico/diagnóstico , Masculino , Enfermedades Mitocondriales/diagnóstico , Enfermedades Musculares/diagnóstico , Proyectos Piloto , Eslovenia , Espectrometría de Masas en Tándem/métodos , Trastornos Innatos del Ciclo de la Urea/diagnósticoAsunto(s)
Ligasas de Carbono-Carbono/deficiencia , Mutación del Sistema de Lectura , Trastornos Hemorrágicos/genética , Eliminación de Secuencia , Factores de Coagulación Sanguínea/metabolismo , Sistemas CRISPR-Cas , Ligasas de Carbono-Carbono/genética , Relación Dosis-Respuesta a Droga , Técnicas de Inactivación de Genes , Genes Reporteros , Células HEK293 , Trastornos Hemorrágicos/sangre , Humanos , Intrones/genética , Unión Proteica , Dominios Proteicos , Procesamiento Proteico-Postraduccional , Estabilidad Proteica , Empalme del ARN/genética , Vitamina K/administración & dosificación , Vitamina K/farmacologíaRESUMEN
OBJECTIVE: To explore the molecular mechanism for a boy suspected with 3-methylcrotonyl-CoA carboxylase deficiency by neonatal screening. METHODS: PCR and Sanger sequencing were used to identify potential mutations of MCCC1 and MCCC2 genes. SIFT and Polyphen-2 software was used to predict the effect of variant on the protein function and conservation of the variant across various species. Human Splicing Finder and Swiss-PdbViewer4.1.0 were applied to analyze the possible mechanism of the variant. RESULTS: For the proband, a compound heterozygous mutation was discovered in the MCCC1 gene, namely c.539G>T (p.G180V) and c.704_711del (p.A235Vfs*4), which were inherited from his father and mother, respectively. The two mutations have disrupted the protein conformation, which in turn may impact the function of MCC protein. CONCLUSION: The compound heterozygous mutations of the MCCC1 gene may contribute to the 3-methylcrotonyl-CoA carboxylase deficiency manifested by the patient.
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Ligasas de Carbono-Carbono/deficiencia , Ligasas de Carbono-Carbono/genética , Mutación , Trastornos Innatos del Ciclo de la Urea/genética , Secuencia de Aminoácidos , Secuencia de Bases , Ligasas de Carbono-Carbono/química , Análisis Mutacional de ADN , Heterocigoto , Humanos , Recién Nacido , Masculino , Modelos Moleculares , Tamizaje Neonatal/métodos , Conformación Proteica , Homología de Secuencia de Aminoácido , Trastornos Innatos del Ciclo de la Urea/diagnósticoRESUMEN
The deficiency of 3-methycrotonyl-CoA carboxylase (3-MCC; EC 6.4.1.4) is an autosomal recessive organic aciduria that is included in the newborn screening programs of several countries. This study reports data mainly obtained from the Portuguese newborn screening program collected over a ten-year period. Analysis of the MCCC1 and MCCC2 genes yielded 26 previously unreported mutations and a variant of clinically unknown significance. These mutations are discussed in the context of their likely impact on the function of the 3-MCC enzyme, with a view to exploring whether a phenotype-genotype correlation might be discerned. Further, these mutations were analysed in the context of what is known of the MCCC1 and MCCC2 mutational spectra, information that will be useful in both clinical and laboratory practice.
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Ligasas de Carbono-Carbono/deficiencia , Errores Innatos del Metabolismo/genética , Mutación , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Tamizaje Masivo , Errores Innatos del Metabolismo/enzimología , PortugalAsunto(s)
Ligasas de Carbono-Carbono/deficiencia , Carnitina/análogos & derivados , Trastornos Innatos del Ciclo de la Urea/sangre , Ácidos Acíclicos/orina , Ligasas de Carbono-Carbono/sangre , Carnitina/administración & dosificación , Carnitina/sangre , Carnitina/uso terapéutico , Cromatografía de Gases y Espectrometría de Masas , Humanos , Recién Nacido , Masculino , Tamizaje Neonatal/normas , Espectrometría de Masas en Tándem , Trastornos Innatos del Ciclo de la Urea/tratamiento farmacológicoRESUMEN
Isolated 3-methylcrotonyl-CoA carboxylase (MCC) deficiency is an autosomal recessive inherited metabolic disease of leucine catabolism with a highly variable phenotype. Apart from extensive mutation analyses of the MCCC1 and MCCC2 genes encoding 3-methylcrotonyl-CoA carboxylase (EC 6.4.1.4), molecular data on MCC deficiency gene expression studies in human tissues is lacking. For IEMs, unbiased '-omics' approaches are starting to reveal the secondary cellular responses to defects in biochemical pathways. Here we present the first whole genome expression profile of immortalized cultured skin fibroblast cells of two clinically affected MCC deficient patients and two healthy individuals generated using Affymetrix(®)HuExST1.0 arrays. There were 16191 significantly differentially expressed transcript IDs of which 3591 were well annotated and present in the predefined knowledge database of Ingenuity Pathway Analysis software used for downstream functional analyses. The most noticeable feature of this MCCA deficient skin fibroblast transcriptome was the typical genetic hallmark of mitochondrial dysfunction, decreased antioxidant response and disruption of energy homeostasis, which was confirmed by mitochondrial functional analyses. The MCC deficient transcriptome seems to predict oxidative stress that could alter the complex secondary cellular response that involve genes of the glycolysis, the TCA cycle, OXPHOS, gluconeogenesis, ß-oxidation and the branched-chain fatty acid metabolism. An important emerging insight from this human MCCA transcriptome in combination with previous reports is that chronic exposure to the primary and secondary metabolites of MCC deficiency and the resulting oxidative stress might impact adversely on the quality of life and energy levels, irrespective of whether MCC deficient individuals are clinically affected or asymptomatic.
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Ligasas de Carbono-Carbono/deficiencia , Fibroblastos/metabolismo , Fibroblastos/patología , Perfilación de la Expresión Génica , Estrés Oxidativo , Piel/citología , Trastornos Innatos del Ciclo de la Urea/metabolismo , Trastornos Innatos del Ciclo de la Urea/patología , Ligasas de Carbono-Carbono/genética , Ligasas de Carbono-Carbono/metabolismo , ADN Mitocondrial/genética , Humanos , Mitocondrias/patología , Mapas de Interacción de Proteínas , Trastornos Innatos del Ciclo de la Urea/genéticaAsunto(s)
Enfermedad del Almacenamiento de Glucógeno Tipo IV/diagnóstico , Enfermedad del Almacenamiento de Glucógeno Tipo IV/enzimología , Hexosaminidasas/sangre , Biopsia , Ligasas de Carbono-Carbono/deficiencia , Ligasas de Carbono-Carbono/genética , Consanguinidad , Análisis Mutacional de ADN , Femenino , Genes Recesivos/genética , Alemania , Enfermedad del Almacenamiento de Glucógeno Tipo IV/genética , Enfermedad del Almacenamiento de Glucógeno Tipo IV/patología , Humanos , Recién Nacido , Macrófagos/patología , Músculo Esquelético/patología , Miofibrillas/patología , Turquía/etnología , Trastornos Innatos del Ciclo de la Urea/diagnóstico , Trastornos Innatos del Ciclo de la Urea/enzimología , Trastornos Innatos del Ciclo de la Urea/genéticaRESUMEN
INTRODUCTION: 3-Methyl crotonyl CoA carboxylase (3MCC) deficiency is an inborn error of leucine metabolism whose detection was increased with the advent of expanded newborn screening. While most NBS-identified infants appear clinically normal, prior studies suggest a possible increased risk for developmental or metabolic abnormalities. As yet, no predictive markers are known that can identify children at risk for biochemical or developmental abnormalities. METHOD: All available 3-MCC cases diagnosed by newborn screening in the Inborn Errors of Metabolism Information System (IBEM-IS) were reviewed for markers that might be predictive of outcome. RESULTS: A limited number of cases were identified with traditional biochemical symptoms including acidosis, hyperammonemia or lactic acidosis, and 15% of those with available developmental information had recorded developmental disabilities not clearly attributable to other causes. There was no correlation between newborn screening (NBS) C5OH level and presence of metabolic, newborn, later-life or developmental abnormalities in these cases. DISCUSSION: This sample, obtained from the IBEM-IS database, attempts to avoid some of the ascertainment bias present in retrospective studies. An increase in developmental abnormalities and in traditionally described metabolic symptoms remains apparent, although no specific biochemical markers appear predictive of outcome. The role that prevention of fasting plays in outcome cannot be ascertained. These data suggest that C5OH level found on newborn screening by itself is not sufficient for diagnostic or predictive purposes.
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Acidosis Láctica/epidemiología , Ligasas de Carbono-Carbono/deficiencia , Discapacidades del Desarrollo/epidemiología , Trastornos Innatos del Ciclo de la Urea/patología , Bases de Datos Factuales , Humanos , Lactante , Recién Nacido , Tamizaje Neonatal , Pronóstico , Estudios RetrospectivosRESUMEN
BACKGROUND: Pseudoxanthoma elasticum (PXE)-like syndrome is characterized by the association of PXE and cutis laxa (CL) features with a deficiency of vitamin K-dependent clotting factors. It was first described in 1971 and was identified as a distinct genetic entity in 2007 with analysis of the GGCX (γ-glutamyl carboxylase) gene, which is involved in congenital deficiency in vitamin K-dependent clotting factors. Here we report a new case of this extremely rare syndrome. PATIENTS AND METHODS: A 23-year-old female patient was seen for the emergence of loose and redundant skin following extensive weight loss. She also presented a deficiency of vitamin K-dependent clotting factors. Physical examination revealed excessive, leathery skin folds in the axillary and neck regions. A skin biopsy revealed polymorphous and fragmented elastic fibers in the reticular dermis. These were mineralized, as was demonstrated by Von Kossa staining. The clinical features of CL associated with the histopathological features of PXE and vitamin K-dependent clotting factor deficiency led us to a diagnosis of PXE-like syndrome. A molecular study of the GGCX gene showed compound heterozygosity. DISCUSSION: The GGCX gene is usually responsible for PXE-like syndrome. GGCX encodes a γ-glutamyl carboxylase necessary for activation of gla-proteins. Gla-proteins are involved both in coagulation factors in the liver and in the prevention of ectopic mineralization of soft tissues. Uncarboxylated forms of gla-proteins in fibroblast would thus enable mineralization and fragmentation of elastic fibers.
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Ligasas de Carbono-Carbono/deficiencia , Trastornos de las Proteínas de Coagulación/diagnóstico , Cutis Laxo/diagnóstico , Seudoxantoma Elástico/diagnóstico , Biopsia , Ligasas de Carbono-Carbono/genética , Trastornos de las Proteínas de Coagulación/genética , Trastornos de las Proteínas de Coagulación/patología , Cutis Laxo/genética , Cutis Laxo/patología , Femenino , Heterocigoto , Humanos , Mutación Missense , Procesamiento Proteico-Postraduccional , Seudoxantoma Elástico/genética , Seudoxantoma Elástico/patología , Piel/patología , Pérdida de Peso , Adulto JovenRESUMEN
BACKGROUND: 3-Methylcrotonyl-CoA carboxylase deficiency (3MCCD) is an inborn error of leucine catabolism. Tandem mass spectrometry newborn screening (NBS) programs worldwide confirmed 3MCCD to be the most common organic aciduria and a relatively benign disorder with favorable outcome. In addition, several asymptomatic 3MCCD mothers were initially identified following abnormal screening of their healthy babies and were appropriately termed maternal 3MCCD. METHODS: This is a retrospective study that summarizes all the clinical, biochemical, and genetic data collected by questionnaires of all 3MCCD individuals that were identified by the extended Israeli NBS program since its introduction in 2009 including maternal 3MCCD cases. RESULTS: A total of 36 3MCCD subjects were diagnosed within the 50-month study period; 16 were classified primary and 20 maternal cases. Four additional 3MCCD individuals were identified following sibling screening. All maternal 3MCCD cases were asymptomatic except for one mother who manifested childhood hypotonia. Most of the primary 3MCCD individuals were asymptomatic except for two whose condition was also complicated by severe prematurity. Initial dried blood spot (DBS) free carnitine was significantly lower in neonates born to 3MCCD mothers compared with newborns with primary 3MCCD (p = 0.0009). Most of the mutations identified in the MCCC1 and MCCC2 genes were missense, five of them were novel. CONCLUSIONS: Maternal 3MCCD is more common than previously thought and its presence may be initially indicated by low DBS free carnitine levels. Our findings provide additional confirmation of the benign nature of 3MCCD and we suggest to exclude this disorder from NBS programs.
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Ligasas de Carbono-Carbono/deficiencia , Trastornos Innatos del Ciclo de la Urea/diagnóstico , Ligasas de Carbono-Carbono/sangre , Ligasas de Carbono-Carbono/genética , Carnitina/sangre , Preescolar , Familia , Femenino , Humanos , Recién Nacido , Israel , Masculino , Mutación/genética , Tamizaje Neonatal/métodos , Estudios Retrospectivos , Encuestas y Cuestionarios , Espectrometría de Masas en Tándem/métodos , Trastornos Innatos del Ciclo de la Urea/sangre , Trastornos Innatos del Ciclo de la Urea/genéticaRESUMEN
Tandem MS "profiling" of acylcarnitines and amino acids was conceived as a first-tier screening method, and its application to expanded newborn screening has been enormously successful. However, unlike amino acid screening (which uses amino acid analysis as its second-tier validation of screening results), acylcarnitine "profiling" also assumed the role of second-tier validation, due to the lack of a generally accepted second-tier acylcarnitine determination method. In this report, we present results from the application of our validated UHPLC-MS/MS second-tier method for the quantification of total carnitine, free carnitine, butyrobetaine, and acylcarnitines to patient samples with known diagnoses: malonic acidemia, short-chain acyl-CoA dehydrogenase deficiency (SCADD) or isobutyryl-CoA dehydrogenase deficiency (IBD), 3-methyl-crotonyl carboxylase deficiency (3-MCC) or ß-ketothiolase deficiency (BKT), and methylmalonic acidemia (MMA). We demonstrate the assay's ability to separate constitutional isomers and diastereomeric acylcarnitines and generate values with a high level of accuracy and precision. These capabilities are unavailable when using tandem MS "profiles". We also show examples of research interest, where separation of acylcarnitine species and accurate and precise acylcarnitine quantification is necessary.
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Acetil-CoA C-Aciltransferasa/deficiencia , Acil-CoA Deshidrogenasa/deficiencia , Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Ligasas de Carbono-Carbono/deficiencia , Carnitina/análogos & derivados , Errores Innatos del Metabolismo Lipídico/diagnóstico , Trastornos Innatos del Ciclo de la Urea/diagnóstico , Acetil-CoA C-Aciltransferasa/sangre , Acetil-CoA C-Aciltransferasa/líquido cefalorraquídeo , Acetil-CoA C-Aciltransferasa/orina , Acil-CoA Deshidrogenasa/sangre , Acil-CoA Deshidrogenasa/líquido cefalorraquídeo , Acil-CoA Deshidrogenasa/orina , Errores Innatos del Metabolismo de los Aminoácidos/sangre , Errores Innatos del Metabolismo de los Aminoácidos/líquido cefalorraquídeo , Errores Innatos del Metabolismo de los Aminoácidos/orina , Betaína/análogos & derivados , Betaína/sangre , Betaína/líquido cefalorraquídeo , Betaína/orina , Ligasas de Carbono-Carbono/sangre , Ligasas de Carbono-Carbono/líquido cefalorraquídeo , Ligasas de Carbono-Carbono/orina , Carnitina/sangre , Carnitina/líquido cefalorraquídeo , Carnitina/orina , Cromatografía Líquida de Alta Presión/métodos , Cromatografía Líquida de Alta Presión/normas , Femenino , Humanos , Recién Nacido , Isomerismo , Errores Innatos del Metabolismo Lipídico/sangre , Errores Innatos del Metabolismo Lipídico/líquido cefalorraquídeo , Errores Innatos del Metabolismo Lipídico/orina , Masculino , Tamizaje Neonatal , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrometría de Masas en Tándem/normas , Trastornos Innatos del Ciclo de la Urea/sangre , Trastornos Innatos del Ciclo de la Urea/líquido cefalorraquídeo , Trastornos Innatos del Ciclo de la Urea/orinaRESUMEN
Magnetic resonance imaging (MRI) and magnetic resonance spectroscopic (MRS) findings in 3-methylcrotonylglycinuria presenting with acute metabolic decompensation in a previously healthy 7-year old female are described. The patient was hospitalized with fever, irritability, gastrointestinal problems, drowsiness, signs of upper motor neuron deficit, and rapidly progressive respiratory distress requiring assisted ventilation. Laboratory workup showed severe metabolic acidosis, and the diagnosis of 3-methylcrotonylglycinuria was established by the mass spectrometry analysis of urine sample. Although initial CT imaging workup was found to be gross normal, subsequent MRI of the brain in the early chronic stage of the disease showed symmetrical ill-defined signal abnormalities within medulla oblongata, pons, inferior cerebellar peduncles, and periventricular white matter in cerebral hemispheres. Diffusion-weighted images were unremarkable. Single-voxel proton MRS showed elevated levels of lactate, branched-chain amino acids, as well as glutamine and glutamate. To the best of our knowledge, this is the first reported case of late onset 3-methylcrotonylglycinuria with complete MRI and MRS workup in the early chronic phase after metabolic crisis.
Asunto(s)
Encéfalo/patología , Ligasas de Carbono-Carbono/deficiencia , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Trastornos Innatos del Ciclo de la Urea/diagnóstico , Ligasas de Carbono-Carbono/metabolismo , Niño , Femenino , Humanos , Protones , Trastornos Innatos del Ciclo de la Urea/metabolismoRESUMEN
Vitamin K is a fat-soluble vitamin that is necessary for blood coagulation. In addition, it has bone-protective effects. Vitamin K functions as a cofactor of γ-glutamyl carboxylase (GGCX), which activates its substrates by carboxylation. These substrates are found throughout the body and examples include hepatic blood coagulation factors. Furthermore, vitamin K functions as a ligand of the nuclear receptor known as steroid and xenobiotic receptor (SXR) and its murine ortholog, pregnane X receptor (PXR). We have previously reported on the bone-protective role of SXR/PXR signaling by demonstrating that systemic Pxr-knockout mice displayed osteopenia. Because systemic Ggcx-knockout mice die shortly after birth from severe hemorrhage, the GGCX-mediated effect of vitamin K on bone metabolism has been difficult to evaluate. In this work, we utilized Ggcx-floxed mice to generate osteoblast-specific GGCX-deficient (Ggcx(Δobl/Δobl)) mice by crossing them with Col1-Cre mice. The bone mineral density (BMD) of Ggcx(Δobl/Δobl) mice was significantly higher than that of control Col1-Cre (Ggcx(+/+)) mice. Histomorphometrical analysis of trabecular bones in the proximal tibia showed increased osteoid volume and a higher rate of bone formation in Ggcx(Δobl/Δobl) mice. Histomorphometrical analysis of cortical bones revealed a thicker cortical width and a higher rate of bone formation in Ggcx(Δobl/Δobl) mice. Electron microscopic examination revealed disassembly of mineralized nodules and aberrant calcification of collagen fibers in Ggcx(Δobl/Δobl) mice. The mechanical properties of bones from Ggcx(Δobl/Δobl) mice tended to be stronger than those from control Ggcx(+/+) mice. These results suggest that GGCX in osteoblasts functions to prevent abnormal mineralization in bone formation, although this function may not be a prerequisite for the bone-protective effect of vitamin K.
Asunto(s)
Calcificación Fisiológica , Ligasas de Carbono-Carbono/deficiencia , Osteoblastos/enzimología , Osteogénesis , Animales , Fenómenos Biomecánicos , Densidad Ósea , Ligasas de Carbono-Carbono/metabolismo , Fémur/patología , Fémur/fisiopatología , Ratones , Especificidad de Órganos , Osteoblastos/patología , Tibia/patología , Tibia/fisiopatología , Tibia/ultraestructuraRESUMEN
BACKGROUND: 3-Methylcrotonyl-CoA carboxylase (3-MCC) deficiency is an autosomal recessively inherited disease of leucine catabolism. It is the most commonly observed organic acidemia where tandem mass spectrometry can be performed in newborn screening. The clinical phenotypes may differ from neurological involvement in newborns to asymptomatic adults. Diagnosis is made by increased 3-hydroxyisovaleric acid in blood and 3-methylcrotonylglycine in urine. CASE REPORT: We would like to present an interesting case of a 32-year-old asymptomatic mother, who was investigated metabolically and diagnosed with 3-MCC deficiency, after a 7-day-old healthy baby referred to our unit with the preliminary diagnosis of organic academia during her extended newborn screening. RESULTS: All of the metabolic findings of the baby were normal except for very low carnitine levels. Her mother's total and free carnitine levels were also extremely low. Urine organic acid analysis revealed excessively increased 3-methylcrotonylglycine and 3-hydroxyisovaleric acid. Acylcarnitine profile showed markedly elevated C5 hydroxy 3 hydroxyisovalerylcarnitine and decreased C2 acetylcarnitine. In order to confirm the diagnosis of 3-methylcrotonylglycinuria, molecular analysis was done, and IVS3-1G>C/p.T556I compound heterozygote mutation was detected. p.T556I is a novel mutation. CONCLUSION: We would like to emphasize performing extended metabolic investigations in case of suspicion of metabolic disease in order to diagnose metabolic diseases both in babies and in asymptomatic mothers.