RESUMEN
Bromination of N-substituted homophthalimides and tetrahydropyrido[4,3-d]- pyrimidine-5,7-diones produces 4,4-dibromohomophthalimide and 8,8-dibromo-tetrahydropyrido[4,3-d]pyrimidine-5,7-dione derivatives, respectively, that can be used as precursors for spiro derivatives. The dibromo derivatives react with different binucleophilic reagents to produce several spiroisoquinoline and spirotetrahydropyrido[4,3-d]- pyrimidine-5,7-dione derivatives, respectively. Reaction of the dibromo derivatives with malononitrile produces dicyanomethylene derivatives which react with different binucleophiles to produce new spiro derivatives. All new compounds are prepared by using the usual chemical conditions and microwave assisted conditions. The latter conditions improved the reaction yields, reduced reaction times and ameliorated the effects on the surrounding environment as the reactions are carried out in closed systems. Structures of the newly synthesized compounds are proved using spectroscopic methods such as IR, MS, 1H-NMR and 13C-NMR and elemental analyses. Some of the newly synthesized compounds were tested for their antimicrobial activities, whereby four of them showed moderate activities and the rest showed low or no activities towards the investigated species.
Asunto(s)
Antibacterianos/síntesis química , Antifúngicos/síntesis química , Pirimidinas/síntesis química , Quinolinas/síntesis química , Compuestos de Espiro/síntesis química , Antibacterianos/farmacología , Antifúngicos/farmacología , Aspergillus niger/efectos de los fármacos , Bacillus subtilis/efectos de los fármacos , Candida albicans/efectos de los fármacos , Pruebas Antimicrobianas de Difusión por Disco , Escherichia coli/efectos de los fármacos , Lactococcus lactis/efectos de los fármacos , Microondas , Penicillium/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Pirimidinas/farmacología , Quinolinas/farmacología , Compuestos de Espiro/farmacologíaRESUMEN
BACKGROUND: We review clinical, neuroimaging, and genetic information on six individuals with isolated sulfite oxidase deficiency (ISOD). METHODS: All patients were examined, and clinical records, biochemistry, neuroimaging, and sulfite oxidase gene (SUOX) sequencing were reviewed. RESULTS: Data was available on six individuals from four nuclear families affected by ISOD. Each individual began to seize within the first week of life. neurologic development was arrested at brainstem reflexes, and severe microcephaly developed rapidly. neuroimaging within days of birth revealed hypoplasia of the cerebellum and corpus callosum and damage to the supratentorial brain looking like severe hypoxic-ischemic injury that evolved into cystic hemispheric white matter changes. Affected individuals all had elevated urinary S-sulfocysteine and normal urinary xanthine and hypoxanthine levels diagnostic of ISOD. Genetic studies confirmed SUOX mutations in four patients. CONCLUSIONS: ISOD impairs systemic sulfite metabolism, and yet this genetic disease affects only the brain with damage that is commonly confused with the clinical and radiologic features of severe hypoxic-ischemic encephalopathy.Lésions neurologiques dans le déficit isolé en sulfite oxydase.
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Errores Innatos del Metabolismo de los Aminoácidos/complicaciones , Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Errores Innatos del Metabolismo de los Aminoácidos/genética , Microcefalia/diagnóstico , Microcefalia/etiología , Sulfito-Oxidasa/deficiencia , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Microcefalia/genética , Linaje , Sulfito-Oxidasa/genéticaRESUMEN
ß-ureidopropionase is the third enzyme of the pyrimidine degradation pathway and catalyzes the conversion of N-carbamyl-ß-alanine and N-carbamyl-ß-aminoisobutyric acid to ß-alanine and ß-aminoisobutyric acid, ammonia and CO(2). To date, only five genetically confirmed patients with a complete ß-ureidopropionase deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 11 newly identified ß-ureidopropionase deficient patients as well as the analysis of the mutations in a three-dimensional framework. Patients presented mainly with neurological abnormalities (intellectual disabilities, seizures, abnormal tonus regulation, microcephaly, and malformations on neuro-imaging) and markedly elevated levels of N-carbamyl-ß-alanine and N-carbamyl-ß-aminoisobutyric acid in urine and plasma. Analysis of UPB1, encoding ß-ureidopropionase, showed 6 novel missense mutations and one novel splice-site mutation. Heterologous expression of the 6 mutant enzymes in Escherichia coli showed that all mutations yielded mutant ß-ureidopropionase proteins with significantly decreased activity. Analysis of a homology model of human ß-ureidopropionase generated using the crystal structure of the enzyme from Drosophila melanogaster indicated that the point mutations p.G235R, p.R236W and p.S264R lead to amino acid exchanges in the active site and therefore affect substrate binding and catalysis. The mutations L13S, R326Q and T359M resulted most likely in folding defects and oligomer assembly impairment. Two mutations were identified in several unrelated ß-ureidopropionase patients, indicating that ß-ureidopropionase deficiency may be more common than anticipated.
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Amidohidrolasas/deficiencia , Amidohidrolasas/genética , Enfermedades del Sistema Nervioso Central/genética , Errores Innatos del Metabolismo de la Purina-Pirimidina/genética , Pirimidinas/metabolismo , Adulto , Secuencia de Aminoácidos , Sustitución de Aminoácidos/fisiología , Ácidos Aminoisobutíricos/sangre , Ácidos Aminoisobutíricos/orina , Animales , Biocatálisis , Dominio Catalítico/fisiología , Enfermedades del Sistema Nervioso Central/enzimología , Niño , Preescolar , Drosophila melanogaster , Escherichia coli , Femenino , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Mutación Missense , Mutación Puntual , Conformación Proteica , Dominios y Motivos de Interacción de Proteínas/fisiología , Errores Innatos del Metabolismo de la Purina-Pirimidina/enzimología , Grupos Raciales/genética , beta-Alanina/sangre , beta-Alanina/orinaRESUMEN
Background and Aims: Transanal endorectal pull-through (TERPT) is a standard procedure for managing paediatric patients with Hirschsprung's disease (HD). This study aimed to evaluate peri-anal infiltration versus caudal block as a part of multimodal analgesia for paediatric patients with HD undergoing the TERPT procedure. Methods: This randomised trial included 60 patients of both genders, aged 6 to 18 months who underwent the TERPT procedure under general anaesthesia. The patients were randomly assigned into two groups to receive either peri-anal infiltration or caudal block with 1 ml/kg bupivacaine 0.25% and dexmedetomidine 1 µg/kg in 0.5 ml normal saline. The primary outcome was the time to the first rescue analgesia. The secondary outcomes were the total consumption, the frequency of nalbuphine administration as rescue analgesia within 24 hours and the level of postoperative sedation. Results: The time to first rescue analgesia was significantly shorter in the peri-anal infiltration group versus the caudal block group (median [interquartile range] 10 [7.5-12.5] h versus 16 [13.5-18.5] h, respectively, P = 0.008). The frequency of administration and the total dose of nalbuphine was significantly higher in the peri-anal infiltration group (P = 0.003 and 0.013, respectively). The sedation score was significantly higher in the caudal block group postoperatively. Conclusion: For paediatric patients undergoing the TERPT procedure, peri-anal infiltration was less effective than caudal block in terms of the duration of postoperative analgesia. However, both techniques were comparable during the first 6 hours postoperatively.
RESUMEN
The T(-13910) variant located in the enhancer element of the lactase (LCT) gene correlates perfectly with lactase persistence (LP) in Eurasian populations whereas the variant is almost nonexistent among Sub-Saharan African populations, showing high prevalence of LP. Here, we report identification of two new mutations among Saudis, also known for the high prevalence of LP. We confirmed the absence of the European T(-13910) and established two new mutations found as a compound allele: T/G(-13915) within the -13910 enhancer region and a synonymous SNP in the exon 17 of the MCM6 gene T/C(-3712), -3712 bp from the LCT gene. The compound allele is driven to a high prevalence among Middle East population(s). Our functional analyses in vitro showed that both SNPs of the compound allele, located 10 kb apart, are required for the enhancer effect, most probably mediated through the binding of the hepatic nuclear factor 1 alpha (HNF1 alpha). High selection coefficient (s) approximately 0.04 for LP phenotype was found for both T(-13910) and the compound allele. The European T(-13910) and the earlier identified East African G(-13907) LP allele share the same ancestral background and most likely the same history, probably related to the same cattle domestication event. In contrast, the compound Arab allele shows a different, highly divergent ancestral haplotype, suggesting that these two major global LP alleles have arisen independently, the latter perhaps in response to camel milk consumption. These results support the convergent evolution of the LP in diverse populations, most probably reflecting different histories of adaptation to milk culture.
Asunto(s)
Lactasa/genética , Leche/metabolismo , Alelos , Animales , Camelus , Cultura , Evolución Molecular , Haplotipos , Humanos , Lactasa/metabolismo , Prueba de Tolerancia a la Lactosa , Medio Oriente , Polimorfismo de Nucleótido Simple , Arabia SauditaRESUMEN
Hereditary Tyrosinemia Type 1 (HT1) is an autosomal recessive disorder resulting from a deficiency of fumarylacetoacetase caused by mutations in the fumarylacetoacetate hydrolase (FAH) gene. We detected 11 novel and 6 previously described pathogenic mutations in a cohort of 43 patients originating from the Middle East with the acute form HT1. All of the mutations were homozygous and we did not find the presence of a "founder mutation".
Asunto(s)
Hidrolasas/genética , Mutación , Tirosinemias/genética , Estudios de Casos y Controles , Consanguinidad , Análisis Mutacional de ADN , Egipto , Estudios de Asociación Genética , Herencia , Homocigoto , Irán , Arabia SauditaRESUMEN
Accumulation of glutaric acid (GA) and 3-hydroxyglutaric acid (3HGA) in body fluids is the biochemical hallmark of type 1 glutaric aciduria (GA1), a disorder characterized by acute striatal degeneration and a subsequent dystonia. To date, methods for quantification of 3HGA are mainly based on stable isotope dilution gas chromatography mass spectrometry (GC-MS) and require extensive sample preparation. Here we describe a simple liquid chromatography tandem MS (LC-MS/MS) method to quantify this important metabolite in dried urine spots (DUS). This method is based on derivatization with 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole (DAABD-AE). Derivatization was adopted to improve the chromatographic and mass spectrometric properties of the studied analytes. Derivatization was performed directly on a 3.2-mm disc of DUS as a sample without extraction. Sample mixture was heated at 60°C for 45 min, and 5 µl of the reaction solution was analyzed by LC-MS/MS. Reference ranges obtained were in excellent agreement with the literature. The method was applied retrospectively for the analysis of DUS samples from established low- and high-excreter GA1 patients as well as controls (n = 100). Comparison of results obtained versus those obtained by GC-MS was satisfactory (n = 14). In populations with a high risk of GA1, this approach will be useful as a primary screening method for high- or low-excreter variants. In these populations, however, DUS analysis should not be implemented before completing a parallel comparative study with the standard screening method (i.e., molecular testing). In addition, follow-up DUS GA and 3HGA testing of babies with elevated dried blood spot C5DC acylcarnitines will be useful as a first-tier diagnostic test, thus reducing the number of cases requiring enzymatic and molecular analyses to establish or refute the diagnosis of GA1.
Asunto(s)
Glutaratos/orina , Espectrometría de Masas en Tándem/métodos , Urinálisis/métodos , Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Errores Innatos del Metabolismo de los Aminoácidos/orina , Encefalopatías Metabólicas/diagnóstico , Encefalopatías Metabólicas/orina , Cromatografía Liquida/métodos , Desecación , Glutaratos/análisis , Glutaril-CoA Deshidrogenasa/deficiencia , Glutaril-CoA Deshidrogenasa/orina , Humanos , Recién Nacido , Tamizaje Neonatal/métodosRESUMEN
Medium-chain acyl-CoA dehydrogenase deficiency (MCADD), caused by mutated ACADM gene, is a potentially fatal fatty acid oxidation defect. Detection of MCADD is now part of tandem mass spectrometry (MS-MS)-based newborn screening programs worldwide. To date, more than 67 mutations have been reported to cause MCADD with a single allele, c.985A>G, being the most common in patients of northwestern European descent. In Saudi Arabia, the Newborn Screening Program, officially launched in 2005, screens for 16 disorders including MCADD. Over a period of 3 years, 237,812 newborns were screened; 13 were identified to have MCADD giving an incidence of 1:18,293. Since the introduction of MS-MS to our institution, however, a total of 30 patients were detected to have MCADD. These cases were either newborns, at high-risk family members, or clinically suspected. The C8-carnitine levels (median 3.31, range 0.81-16.33 µM) were clearly diagnostic in all analyzed samples. Sequencing ACADM in 20 DBS revealed two novel mutations: c.362C>T (p.T121I) and c.347G>A (p.C116Y) substitutions, neither of which were detected in 300 chromosomes from controls. Eighteen (90%) patients were homozygous for the T121I mutation and two (10%) were compound heterozygous (T121I/C116Y). Our molecular data lend further support to MS-MS biochemical screening for MCADD and provide evidence for the relatively high incidence of MCADD in the Arab population. The identification of a founder mutation for MCADD has important implications for the preventive screening programs not only in Saudi Arabia but potentially also in other countries in the region.
Asunto(s)
Acil-CoA Deshidrogenasa/genética , Mutación , Acil-CoA Deshidrogenasa/sangre , Acil-CoA Deshidrogenasa/deficiencia , Biomarcadores/sangre , Carnitina/sangre , Análisis Mutacional de ADN , Pruebas con Sangre Seca , Efecto Fundador , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Pruebas Genéticas/métodos , Humanos , Incidencia , Recién Nacido , Errores Innatos del Metabolismo Lipídico/sangre , Errores Innatos del Metabolismo Lipídico/diagnóstico , Errores Innatos del Metabolismo Lipídico/enzimología , Errores Innatos del Metabolismo Lipídico/epidemiología , Errores Innatos del Metabolismo Lipídico/genética , Errores Innatos del Metabolismo Lipídico/prevención & control , Tamizaje Neonatal/métodos , Fenotipo , Valor Predictivo de las Pruebas , Arabia Saudita/epidemiología , Espectrometría de Masas en TándemRESUMEN
OBJECTIVE: Prenatal diagnosis of Canavan disease by measuring N-acetylaspartic acid (NAA) in amniotic fluid is reliable and preferred over aspartoacylase enzyme assay especially in populations with unknown mutations. Typically based on GC-MS, existing methods are time-consuming and laborious. We developed a novel LC-MS/MS method for determination of NAA in amniotic fluid with minimal sample preparation. METHOD: NAA and d(3)-NAA were detected by negative-ion electrospray ionization-MS/MS. Quantification was achieved by standard addition using six 0.1 mL portions of each specimen enriched with increasing NAA amounts (0, 0.05, 0.1, 0.2, 0.3, and 0.4 microg) and endogenous NAA was calculated by extrapolation. RESULTS: Injection-to-injection time was 2 min whereas the turn around time from sample receipt was about 1 h. Intraday (n = 10) and interday (n = 10) variations were less than 9.4%. The reference range determined using gestation-matched controls (n = 12) of 1.1-2.7 micromol/L is in agreement with the literature. Specimens from at-risk pregnancies with established diagnosis (n = 4) were successfully analyzed. CONCLUSION: We developed a new method that enables reliable, sensitive, and selective determination of NAA in a small volume of amniotic fluid for the prenatal diagnosis of Canavan disease. The simple sample preparation adopted in this work precluded the necessity for extraction and derivatization.
Asunto(s)
Líquido Amniótico/química , Ácido Aspártico/análogos & derivados , Enfermedad de Canavan/diagnóstico , Diagnóstico Prenatal/métodos , Espectrometría de Masas en Tándem/métodos , Amidohidrolasas/genética , Ácido Aspártico/análisis , Enfermedad de Canavan/etiología , Enfermedad de Canavan/genética , Enfermedad de Canavan/patología , Estudios de Casos y Controles , Cromatografía Liquida/métodos , Femenino , Edad Gestacional , Humanos , Mutación/fisiología , Embarazo , Reproducibilidad de los Resultados , Factores de RiesgoRESUMEN
The aim of the study was to investigate the prevalence and mechanisms of development of carnitine deficiency in patients with lysinuric protein intolerance (LPI). In our cohort of 37 Finnish patients with LPI, 8 (8-52 years of age) have been diagnosed with hypocarnitinemia. Their free and total serum carnitine levels, acyl carnitine profiles, renal function, diet, and medication were compared with the data from 8 age- and sex-matched patients with LPI not treated with carnitine supplementation. In patients with LPI, hypocarnitinemia was strongly associated with female sex, renal insufficiency, and the use of ammonia-scavenging drugs. Of the 8 hypocarnitinemic patients, 3 complained of muscle weakness, and their symptoms disappeared during carnitine supplementation. Oral lysine supplementation did not correct hypocarnitinemia in our patients. The patients with LPI are at considerable risk for carnitine deficiency. Supplementation of hypocarnitinemic LPI patients with oral L-carnitine improved serum total carnitine values, but the ratio of free and total carnitine remained subnormal in all supplemented patients except one. Furthermore, decreased ratio of free and total serum carnitine was common even in LPI patients with normal total serum carnitine concentration.
Asunto(s)
Errores Innatos del Metabolismo de los Aminoácidos/metabolismo , Carnitina/deficiencia , Lisina/orina , Adolescente , Adulto , Errores Innatos del Metabolismo de los Aminoácidos/terapia , Niño , Suplementos Dietéticos , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is an autosomal recessive disorder caused by mutations in ORNT1 gene that encodes a mitochondrial ornithine transporter. It has variable clinical presentations with episodic hyperammonemia, liver dysfunction, and chronic neurological manifestations. In this work, we report the findings of HHH syndrome in 3 Saudi siblings. The 4-year-old proband presented with recurrent Reye-like episodes, hypotonia, and multiple stroke-like lesions on brain MRI. Biochemical and molecular analysis confirmed that she had HHH syndrome. She significantly improved on protein restriction and sodium benzoate. Her two older siblings have milder phenotypes with protein intolerance and learning problems. In comparison to their sister, their homocitrulline and orotic acid were only mildly elevated even before treatment. The three patients were homozygous for a novel mutation in ORNT1 with a Gly220Arg change. In view of the CNS lesions, which initially were felt to be suggestive of MELAS, we sequenced the entire mtDNA genome and no potential pathogenic mutations were detected. Analysis of ORNT2 did not provide explanation of the clinical and biochemical variability. This work presents a yet unreported CNS involvement pattern, notably multiple supratentorial stroke-like lesions in association with HHH syndrome. Moreover, it illustrates considerable clinical/biochemical correlation, and describes a novel mutation. We suggest including HHH syndrome in the differential diagnosis of patients found to have stroke-like lesions on brain MRI.
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Errores Innatos del Metabolismo de los Aminoácidos/genética , Errores Innatos del Metabolismo de los Aminoácidos/fisiopatología , Sistemas de Transporte de Aminoácidos Básicos/genética , Encefalopatías Metabólicas Innatas/genética , Encefalopatías Metabólicas Innatas/fisiopatología , Predisposición Genética a la Enfermedad/genética , Adolescente , Errores Innatos del Metabolismo de los Aminoácidos/metabolismo , Encéfalo/metabolismo , Encéfalo/patología , Encéfalo/fisiopatología , Encefalopatías Metabólicas Innatas/metabolismo , Niño , Preescolar , Citrulina/análogos & derivados , Citrulina/metabolismo , Análisis Mutacional de ADN , Femenino , Alimentos Formulados , Marcadores Genéticos/genética , Pruebas Genéticas , Genotipo , Humanos , Hiperamonemia/genética , Hiperamonemia/metabolismo , Hiperamonemia/fisiopatología , Imagen por Resonancia Magnética , Masculino , Proteínas de Transporte de Membrana Mitocondrial , Mutación/genética , Ornitina/metabolismo , Linaje , Arabia Saudita , Benzoato de Sodio/uso terapéutico , Accidente Cerebrovascular/genética , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/fisiopatologíaAsunto(s)
Errores Innatos del Metabolismo de los Aminoácidos/diagnóstico , Errores Innatos del Metabolismo de los Aminoácidos/genética , Salud de la Familia , Mutación/genética , Sulfito-Oxidasa/genética , Niño , Cromosomas Humanos Par 12/genética , Consanguinidad , Análisis Mutacional de ADN , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Embarazo , Sudán , Sulfito-Oxidasa/deficiencia , Tomografía Computarizada por Rayos XRESUMEN
We describe an improved diagnostic method for tyrosinemia type 1 based on quantifying succinylacetone in dried blood spots by ultra-performance liquid chromatography tandem mass spectrometry. Succinylacetone extracted from a single 3/16 inch disk of specimen collection paper containing a dried blood spot was derivatized with dansylhydrazine, separated on an Acquity UPLC BEH C(18) column (2.1 x 50 mm, 1.7 microm) and detected by electrospray ionization tandem mass spectrometry. Succinylacetone derivative eluted at 0.6 min with a complete run time of 1 min. Using a 13C4 labeled succinylacetone as an internal standard, the calibration plot was linear up to 100 micromol/L with a detection limit (S/N = 3) of 0.2 micromol/L. Intra-day (n = 13) and inter-day (n = 10) variations were better than 10%. The cutoff level of succinylacetone in dried blood spots from healthy infants obtained by the current method was 0.63 micromol/L (n = 151). In dried blood spots from patients with established tyrosinemia type 1 (n = 11), concentration of succinylacetone was 6.4-30.8 micromol/L.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Heptanoatos/sangre , Espectrometría de Masa por Ionización de Electrospray/métodos , Espectrometría de Masas en Tándem/métodos , Tirosinemias/diagnóstico , Heptanoatos/química , Humanos , Modelos Lineales , Tirosinemias/sangreRESUMEN
BACKGROUND: Hepatorenal tyrosinemia (HT1) is considered a treatable inherited metabolic disease, particularly when detected early in life. Succinylacetone (SA), a unique metabolic marker for HT1, is normally circulating or excreted at very low physiological concentrations and is significantly increased in HT1 patients. METHODS: We developed and validated a new method for the determination of SA in urine using high-pressure liquid chromatography with fluorescence detection. SA and its homologue 5,7-dioxooctanoic acid used as internal standard (IS) were extracted from urine, derivatized with pyrenebutyric hydrazide and separated on a C18 column within 11 min. Calibration curves were linear between 0.025 to 100 micromol/l. Within- and between-day variations were <5% and results obtained by the current method compared favorably with a reference liquid chromatography tandem mass spectrometric method. The method was applied retrospectively to the analysis of urine samples from HT1 patients. CONCLUSIONS: The method requires a minimal sample volume (0.1 ml) with simple instrumentation. The method enabled us to differentiate HT1 cases (n=14) from controls (n=104), regardless of the years of urine storage.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Heptanoatos/orina , Enfermedades Renales/orina , Hepatopatías/orina , Espectrometría de Fluorescencia/métodos , Tirosinemias/orina , Calibración , HumanosRESUMEN
Succinylacetone (SA) is a specific marker for the inherited metabolic disease, hepatorenal tyrosinemia. We developed a stable-isotope dilution liquid chromatography tandem mass spectrometry for the determination of SA in dried blood spots (DBS) and liquid urine using a (13)C(4)-SA as internal standard. SA was extracted, converted to the butyl ester and derivatized with dansylhydrazine (Dns-H). Calibration curves in DBS and urine calibrators were linear up to 100 and 30 microM, respectively. At a signal-to-noise ratio of 3, the limits of detection in DBS and urine were 0.2 and 0.005 microM, respectively. Total run time was 5 min. Intra- and inter-assay precision expressed as coefficient of variation were better than 9.1% with more than 96% recovery. The method was applied retrospectively and prospectively for the diagnosis of hepatorenal tyrosinemia and for follow-up of patients under treatment.
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Cromatografía Líquida de Alta Presión/métodos , Heptanoatos/sangre , Heptanoatos/orina , Compuestos de Dansilo/química , Heptanoatos/química , Humanos , Hidrazinas/química , Recién Nacido , Espectrometría de Masas/métodos , Tamizaje Neonatal/métodos , Manejo de Especímenes , Tirosinemias/diagnósticoRESUMEN
Defects in the human gene encoding methylmalonyl-CoA mutase enzyme (MCM) give rise to a rare autosomal recessive inherited disorder of propionate metabolism termed mut methylmalonic acidemia (MMA). Patients with mut MMA have been divided into two subgroups: mut0 with complete loss of MCM activity and mut- with residual activity in the presence of adenosylcobalamin (AdoCbl). The disease typically presents in the first weeks or months of life and is clinically characterized by recurrent vomiting, metabolic acidosis, hyperammonemia, lethargy, poor feeding, failure to thrive and neurological deficit. To better elucidate the spectrum of mutations causing mut MMA in Saudi patients, we screened a cohort of 60 Saudi patients affected by either forms of the disease for mutations in the MUT gene. A total of 13 different mutations, including seven previously reported missense changes and six novel mutations, were detected in a homozygous state except for two compound heterozygous cases. The six novel mutations identified herein consist of three nonsense, two missense and one frameshift, distributed throughout the whole protein. This study describes for the first time the clinical and mutational spectrum of mut MMA in Saudi Arabian patients.
RESUMEN
BACKGROUND: Glutaric aciduria type I (GA1) is an autosomal recessive disorder that usually causes neurological damage. Early diagnosis of the disease prior to the appearance of clinical symptoms can lead to better outcomes. METHODS: We describe a simple and selective HPLC method with intramolecular excimer-forming fluorescence derivatization to diagnose GA1. Glutaric acid (GA) and 3-hydroxyglutaric acid (3HGA) in urine and an internal standard were derivatized with 1-pyrenebutyric hydrazide (PBH). The derivatives were separated on a C18 column and fluorometrically detected at 475 nm (excitation of 345 nm) with a run time of 18 min. RESULTS: Excellent linearity over a wide range, reproducibility (coefficient of variation < or =14.5%), and sensitivity (limit of detection 0.4 micromol/l 3HGA and 0.2 micromol/l GA) were obtained. A retrospective study on previously diagnosed GA1 patients' urine from our laboratory archives between 1999 and 2004 was performed by analysts blinded to the study. CONCLUSIONS: The method enabled us to differentiate GA1 cases (n=36) from controls (n=99), regardless of the years of urine storage. The method is valuable for both retrospective and prospective diagnoses of GA1.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Glutaratos/orina , Errores Innatos del Metabolismo/orina , Espectrometría de Fluorescencia/métodos , Estudios de Casos y Controles , Glutaratos/sangre , Humanos , Estándares de Referencia , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
This case report profiles two children whose sole presentation is intractable seizures. The index case is a 1-year-old female. She presented to the emergency department with intractable seizures. Her initial metabolic evaluation was nonconclusive. Electroencephalogram was abnormal. Brain magnetic resonance imaging yielded a picture consistent with profound ischemic hypoxic injury. The second case was the 8-year-old brother of the index case. He suffered from intractable seizures since birth. On examination he was microcephalic with spastic quadriparesis and bilateral dislocation of lenses. Computed tomography of the brain revealed a low-density area in the white and cortical matter consistent with hypoxic-ischemic injury. His urinalysis for sulfocysteine produced findings consistent with isolated sulfite oxidase deficiency.
Asunto(s)
Hipoxia-Isquemia Encefálica/etiología , Errores Innatos del Metabolismo/complicaciones , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro/deficiencia , Encéfalo/patología , Niño , Femenino , Humanos , Hipoxia-Isquemia Encefálica/patología , Lactante , Masculino , Errores Innatos del Metabolismo/patología , Convulsiones/etiología , Convulsiones/patologíaRESUMEN
Accumulation of propionylcarnitine (C3) in neonatal dried blood spots (DBS) is indicative of inborn errors of propionate metabolism including propionic acidemia (PA), methylmalonic aciduria (MMA), and cobalamin (Cbl) metabolic defects. Concentrations of C3 in affected newborns overlap with healthy individuals rendering this marker neither specific nor sensitive. While a conservative C3 cutoff together with relevant acylcarnitines ratios improve screening sensitivity, existing mass spectrometric methods in newborn screening laboratories are inadequate at improving testing specificity. Therefore, using the original screening DBS, we sought to measure 2-methylcitric acid (MCA), a pathognomonic hallmark of C3 disorders to decrease the false positive rate and improve the positive predictive value of C3 disorders. MCA was derivatized with 4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole (DAABD-AE). No separate extraction step was required and derivatization was performed directly using a 3.2-mm disc of DBS as a sample (65°C for 45 min). The reaction mixture was analyzed by liquid chromatography tandem mass spectrometry. MCA was well separated and eluted at 2.3 min with a total run time of 7 min. The median and (range) of MCA of 0.06 µmol/L (0-0.63) were in excellent agreement with the literature. The method was applied retrospectively on DBS samples from established patients with PA, MMA, Cbl C, Cbl F, maternal vitamin B12 deficiency (n = 20) and controls (n = 337). Comparison with results obtained by another method was satisfactory (n = 252). This method will be applied as a second tier test for samples which trigger positive PA or MMA results by the primary newborn screening method.
RESUMEN
BACKGROUND: Hereditary tyrosinemia type 1 (HT1) is an increasingly recognized inborn error of metabolism among Egyptian children. This study was undertaken to define the presenting clinical, biochemical and imaging features and outcome of 2-(2-motrp-4-trifluoromethylbenzoyl)-1, 3-cyclohexanedione (NTBC) therapy and liver transplantation in a cohort of Egyptian children diagnosed with HT1. METHODS: The study was carried out at the Pediatric Hepatology Unit at Cairo University Children's Hospital. HT1 was diagnosed by quantification of succinylacetone (SA) in dry blood spots. RESULTS: Twenty-two patients were diagnosed with HT1 in a period of 3 years from August 2006 to July 2009. Infants with focal hepatic lesions and hepatomegaly (n=13) were younger at diagnosis than those with rickets (n=5) (median age: 3.25 vs. 10 months; P=0.05). Alpha fetoprotein was highly elevated in all children. Seven children died within a few weeks of diagnosis before therapy was initiated. Ten children were treated with NTBC. The response to NTBC treatment was apparent by a steep drop in serum alpha fetoprotein (AFP) and undetectable SA in urine within 2 months. Three children underwent living donor liver transplantation after treatment with NTBC for 10, 18 and 22 months respectively, despite adequate response to therapy because of financial issues. The explanted livers were all cirrhotic with no dysplasia or malignant transformation. CONCLUSIONS: Focal hepatic lesions are the commonest presentation of HT1 patients and they present at an earlier age than rickets. NTBC is effective but very expensive. Liver transplantation is still considered in HT1 patients.