Independent origin for m.3243A>G mitochondrial mutation in three Venezuelan cases of MELAS syndrome.

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a multisystem and progressive neurodegenerative mitochondrial disease, caused by point nucleotide changes in the mtDNA where 80 % of cases have the mutation m.3243A>G in the MT-TL1 gene. In this work, we described the clinical, biochemical and molecular analysis of three Venezuelan patients affected with MELAS syndrome. All cases showed lactic acidosis, cortical cerebral atrophy on magnetic resonance imaging and muscular system deficit, and in two of the cases alteration of urine organic acid levels was also registered. A screening for the mutation m.3243A>G in different patients' body samples confirmed the presence of this mutation with variable degrees of heteroplasmy (blood = 7-41 %, buccal mucosa = 14-53 %, urine = 58-94 %). The mitochondrial haplogroups for the three patients were different (H, C1b, and A2), indicating an independent origin for the mutation.

Current Practices and Challenges in the Diagnosis and Management of PKU in Latin America: A Multicenter Survey.

This study aimed to describe the current practices in the diagnosis and dietary management of phenylketonuria (PKU) in Latin America, as well as the main barriers to treatment. We developed a 44-item online survey aimed at health professionals. After a pilot test, the final version was sent to 25 practitioners working with inborn errors of metabolism (IEM) in 14 countries. Our results include 22 centers in 13 countries. Most countries (12/13) screened newborns for PKU. Phenylalanine (Phe) targets at different ages were very heterogeneous among centers, with greater consistency at the 0-1 year age group (14/22 sought 120-240 µmol/L) and the lowest at >12 years (10 targets reported). Most countries had only unflavored powdered amino acid substitutes (10/13) and did not have low-protein foods (8/13). Only 3/13 countries had regional databases of the Phe content of foods, and only 4/22 centers had nutrient analysis software. The perceived obstacles to treatment were: low purchasing power (62%), limited/insufficient availability of low-protein foods (60%), poor adherence, and lack of technical resources to manage the diet (50% each). We observed a heterogeneous scenario in the dietary management of PKU, and most countries experienced a lack of dietary resources for both patients and health professionals.

Obtención de hidrolizados proteicos bajos en fenilalanina a partir de suero dulce de leche y chachafruto (Erythrina edulis Triana) / Obtaining protein products low in phenylalanine from milk whey and chachafruto (Erythrina edulis Triana)

La fenilcetonuria (PKU) es causada por una actividad deficiente de la enzima fenilalanina hidroxilasa. En los pacientes con esta deficiencia la fenilalanina (Phe) no puede ser convertida en tirosina, aumentando sus niveles en sangre y de otros metabolitos neurotóxicos, provocando un retraso mental irreversible. El tratamiento fundamentalmente se basa en una dieta controlada de Phe. Sin embargo, los alimentos libres o bajos en Phe son escasos. El objetivo de esta investigación es obtener hidrolizados proteicos con bajo contenido de Phe a partir del suero dulce de leche en polvo y harina de E. edulis Triana. El aislado proteico (96,01% proteína cruda) se obtuvo por solubilización y precipitación de las proteínas de la harina, mientras que las proteínas del suero (15,69% proteína cruda) fueron tratadas en su matriz original. Las proteínas del suero y el asilado fueron hidrolizadas enzimáticamente con pepsina y proteasa de Streptomyces griseus. La concentración de Phe se determinó por fluorometría y por HPLC, de lo cual la Phe de las proteínas del suero es liberada una hora antes que las del chachafruto, debido a que las proteínas del suero en parte fueron hidrolizadas en la elaboración del queso. Además, los resultados de la utilización del carbón activados como captor de Phe indican la reducción total del contenido de este aminoácido en los hidrolizados y la reducción de la concentración de otros aminoácidos(AU)

henylketonuria (PKU) is caused by a low activity of the enzyme phenylalanine hydroxylase. In patients with this deficiency, phenylalanine (Phe) cannot be converted to tyrosine, increasing blood levels and other neurotoxic metabolites, causing irreversible mental retardation. The treatment is fundamentally based on a controlled diet of Phe. However, free or low-Phe foods are scarce. The objective of this research is to obtain protein hydrolysates with low Phe content from sweet milk powder and E. edulis Triana flour. The protein isolate (96.01% crude protein) was obtained by solubilization and precipitation of the flour proteins, while the whey proteins (15.69% crude protein) were treated in their original matrix. Serum and asylated proteins were enzymatically hydrolyzed with pepsin and Streptomyces griseus protease. The concentration of Phe was determined by fluorometry and by HPLC, from which the Phe of whey proteins is released one hour earlier than those of chachafruto, due to the fact that the whey proteins were partially hydrolyzed in the elaboration of the cheese. In addition, the results of the use of charcoal activated as Phe captor indicate the total reduction of the content of this amino acid in the hydrolysates and the reduction of the concentration of other amino acids(AU)

Errores innatos del metabolismo: una aproximación diagnóstica / Inborn errors of metabolism: a diagnostic approach

Los errores innatos del metabolismo (EIM), son enfermedades hereditarias, que obedecen generalmente a alteraciones enzimáticas. Al considerarlas en particular son raras, pero en conjunto representan una importante causa de morbi-mortalidad en la edad pediátrica. El diagnóstico es complicado, ya que las presentaciones clínicas son variadas y poco especificas, y además requieren de investigaciones de laboratorio especializadas. Se clasifican en tres grandes grupos, de acuerdo a los mecanismos fisiopatológicos implicados: los trastornos del metabolismo intermediario, los que obedecen al déficit en la producción de energía y por depósitos de macromoléculas. El conocimiento de los EIM por parte del clínico es fundamental, esto permitirá identificar los datos orientadores de la historia médica y del laboratorio, y solicitar las investigaciones requeridas para un diagnóstico temprano y un tratamiento oportuno.

The inborn errors of metabolism are hereditary diseases caused in most of the cases by enzimatic disturbs. These diseases are rare, but all of them are a very much important cause of morbi – mortality in children. The diagnoses is complicated because clinical presentations are so many and some specific and besides require specialized laboratory investigations. These diseases are classified in three groups, in order to the pshysiopathological mechanisms implicated: intermediary metabolism trastorns, energy production deficit and macromolecules depots. The clinician knowledgement about these diseases is crucial, because it will allow to identify clinical and laboratory dates and apply for required investigations in order to an early diagnosis and opportune treatment.

[Diagnosis and treatment of methylmalonic aciduria: a case report]. / Diagnóstico y tratamiento de la aciduria metilmalónica: a propósito de un caso.

The methylmalonic aciduria is an organic acidemia, inherited as autosomic recessive trait, caused by a deficiency of the methylmalonyl-CoA mutase, or by defects in the biosynthesis of the cofactor adenosylcobalamin. Regarding the enzymatic defect, there are two forms: mut(o) with no detectable enzymatic activity and mut(-) with reduced activity. Its clinical presentation may vary from a severe neonatal form with acidosis and death, up to a progressive chronic form. Here we describe the case of a four year-old boy, with diagnosis of methylmalonyl-CoA mutase deficiency type mut(-) with an acute presentation. Molecular analysis of MUT gene identified two mutations c.607G>A (G203R) and c.2080C>T (R694W), later confirmed in the parents. The aim of this report is to highlight the importance of including the organic acid analysis in urine among the first line exams in acutely and severely ill children with undefined etiology. The definitive diagnosis is important because it may allow a specific treatment and a favorable evolution to prevent the secuelae.

Diagnóstico y tratamiento de la aciduria metilmalónica: a propósito de un caso / Diagnosis and treatment of methylmalonic aciduria: a case report

La aciduria metilmalónica es una acidemia orgánica, autosómica recesiva, causada por la deficiencia de la metilmalonil CoA-mutasa, o por defectos en la biosíntesis del cofactor adenosilcobalamina. Del defecto enzimático, existen dos formas: mut (o) sin actividad enzimática y mut (-) con actividad reducida. Su presentación clínica puede variar desde una forma neonatal grave con acidosis y muerte, hasta una forma crónica progresiva. A continuación se describe el caso de un niño de 4 años de edad, con deficiencia de metilmalonil-CoA mutasa tipo mut (-), que se presentó en forma aguda. El estudio molecular del gen MUT mostró 2 mutaciones c.607G>A (G203R) y c.2080C > T(R694W), confirmadas posteriormente en los padres. El objetivo de este reporte es destacar la importancia de indicar el análisis de ácidos orgánicos en orina entre los estudios de primera línea, en todo niño con un cuadro clínico de presentación aguda y severamente enfermo, sin etiología definida. Por otra parte, se desea resaltar que el diagnóstico oportuno y definitivo es importante ya que permite iniciar un tratamiento específico, lograr una evolución favorable y prevenir las secuelas.