Asociación del espectro autista con patología mitocondrial / Association between autistic spectrum and mitochondrial pathology

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Hepatomioneuropatía secundaria a depleción del ADN mitocondrial / Hepatomioneuropathy secondary to mitochondrial DNA depletion

Introducción. La depleción del ADN mitocondrial (ADNmt) consiste en la presencia de un menor número de copias del genoma mitocondrial, siendo sus expresiones fenotípicas muy heterogéneas. Caso clínico. Niña de 22 meses de edad que presenta hipotonía generalizada detectada a partir de los 7 meses de edad asociada a hepatoesplenomegalia con moderada elevación de la transaminasemia, sin datos de fracaso hepático funcional ni hipoglucemia hipocetótica; progresivamente se observó el desarrollo de debilidad muscular, fracaso respiratorio, hipertensión arterial, acidosis láctica y superposición de signos miopáticos y neuropáticos en los estudios neurofisiológicos periféricos. El estudio genético molecular para la atrofia muscular espinal fue normal. El examen con microscopía óptica de la biopsia muscular fue compatible con atrofia neurogénica, con presencia en el examen ultraestructural de gotas lipídicas, acúmulos mitocondriales subsarcolémicos y de gránulos de glucógeno. Los complejos de la cadena respiratoria mitocondrial (CRM) en homogenado muscular fueron normales. El estudio genético molecular a nivel muscular demostró la presencia de una depleción del ADNmt. Conclusiones. Esta observación probablemente represente una nueva expresión fenotípica de depleción del ADNmt que se puede denominar forma hepatomioneuropática. La normalidad de la CRM en músculo no excluye la depleción del ADNmt

Introduction. Mitochondrial DNA depletion (mtDNA) is an highly heterogeneous condition characterized by a decresed number of mtDNA copies. Case report. The patient is a 22-month-old girl with generalized hypotonia, marked weakness, respiratory failure, arterial hypertension, hyperlactacidemia, hepatosplenomegaly and mild hypertransaminasemia without hepatic failure neither hypoketotic hypoglycemia. Electromyographic findings were consistent with neuromyopathy and muscle biopsy suggested a neurogenic atrophy. Electron microscopy revealed lipid droplets, subsarcolemmal accumulation of mitochondrias and glycogen granules. Respiratory chain enzime activities were normal. Genetic study in muscle showed mtDNA depletion, and the diagnosis of spinal muscular atrophy caused by survival motoneuron gene deletion was excluded. Conclusions. This case might be a novel phenotype of mtDNA depletion which could be named hepatomioneuropatyc form. A normal result of respiratory chain enzimes in muscle doesn't excluded mtDNA depletion

[Hepatomioneuropathy secondary to mitochondrial DNA depletion]. / Hepatomioneuropatía secundaria a depleción del ADN mitocondrial.

INTRODUCTION: Mitochondrial DNA depletion (mtDNA) is an highly heterogeneous condition characterized by a decreased number of mtDNA copies. CASE REPORT: The patient is a 22-month-old girl with generalized hypotonia, marked weakness, respiratory failure, arterial hypertension, hyperlactacidemia, hepatosplenomegaly and mild hypertransaminasemia without hepatic failure neither hypoketotic hypoglycemia. Electromyographic findings were consistent with neuromyopathy and muscle biopsy suggested a neurogenic atrophy. Electron microscopy revealed lipid droplets, subsarcolemmal accumulation of mitochondrias and glycogen granules. Respiratory chain enzime activities were normal. Genetic study in muscle showed mtDNA depletion, and the diagnosis of spinal muscular atrophy caused by survival motoneuron gene deletion was excluded. CONCLUSIONS: This case might be a novel phenotype of mtDNA depletion which could be named hepatomioneuropatyc form. A normal result of respiratory chain enzimes in muscle doesn't excluded mtDNA depletion.

[Mitochondrial respiratory chain diseases. Evaluation and variability in 52 patients]. / Enfermedades de la cadena respiratoria mitocondrial. Evaluación y variabilidad en 52 pacientes.

INTRODUCTION: Clinical, electrophysiological, genetic and biochemical deficiencies variability were evaluated in 52 patients diagnosed of mitochondrial respiratory chain diseases (MRCD). PATIENTS AND METHODS: 26 men and 26 women, aged 19 to 79 years, were tested by clinical examination, electrophysiological techniques, muscle biopsy and genetic and biochemical studies. RESULTS: The patients were classified into seven phenotypes: myopathy, chronic progressive external ophthalmoplegia, progressive ophthalmoplegia plus ataxia, Kearns-Sayre syndrome, mitochondrial encephalomyopathy with lactic acidosis and stroke episodes (MELAS), myoclonic encephalopathy with ragged-red fibers (MERRF), and encephalopathies. Each phenotype may begin by different ways. The electromiography showed myopathy in 39 cases and various types of neuropathy in 10. Ragged-red COX negative fibers or widespread electron microscopic abnormalities were found in 47 cases. Simple deletions, multiple deletions and three different point mutations were observed. Deficiency of complexes I, II, III and IV were found alone or in different associations. CONCLUSIONS: MRCD shows wide variations in clinical, genetic and biochemical studies. Some patients with nonspecific manifestations, mainly of central nervous system, need careful attention and to be on account of diagnostic suspicion.

Enfermedades de la cadena respiratoria mitocondrial. Evaluación y variabilidad en 52 pacientes / Mitochondrial respiratory chain diseases. Evaluation and variability in 52 patients

Introducción. La variabilidad clínica, electrofisiológica, de las deficiencias bioquímicas y genéticas se evaluó en 52 pacientes diagnosticados de enfermedades de la cadena respiratoria mitocondrial (ECRM). Pacientes y métodos. Se evaluó a 26 hombres y 26 mujeres, de edades comprendidas entre 19 y 79 años, mediante exploración clínica, técnicas electrofisiológicas, biopsia de músculo y estudios bioquímico y genético. Resultados. Se clasificó a los pacientes en siete fenotipos: miopatía, oftalmoplejía externa progresiva crónica, oftalmoplejía progresiva plus con ataxia, síndrome de Kearns-Sayre, encefalomiopatía mitocondrial con acidosis láctica y episodios de ictus (MELAS), encefalopatía mioclónica con fibras rojo rasgadas (MERRF) y encefalopatía. Cada fenotipo puede debutar de forma diferente. La electromiografía mostró miopatía en 39 casos y diferentes tipos de neuropatía en 10. En 47 casos se puso de manifiesto la presencia de fibras rojo rasgadas COX negativas o alteraciones mitocondriales prominentes al microscopio electrónico. Se observaron deleciones simples y múltiples, así como tres mutaciones puntuales diferentes. Se encontraron deficiencias de los complejos I, II, III y IV aisladas o en diferentes asociaciones. Conclusiones. Las ECRM muestran grandes diferencias entre ellas en los estudios clínicos, bioquímicos y genéticos. Algunos pacientes con manifestaciones inespecíficas, principalmente del sistema nervioso central, requieren una atención cuidadosa y que se plantee la sospecha diagnóstica de ECRM (AU)

Introduction. Clinical, electrophysiological, genetic and biochemical deficiencies variability were evaluated in 52 patients diagnosed of mitochondrial respiratory chain diseases (MRCD). Patients and methods. 26 men and 26 women, aged 19 to 79 years, were tested by clinical examination, electrophysiological techniques, muscle biopsy and genetic and biochemical studies. Results. The patients were classified into seven phenotypes: myopathy, chronic progressive external ophthalmoplegia, progressive ophthalmoplegia plus ataxia, Kearns-Sayre syndrome, mitochondrial encephalomyopathy with lactic acidosis and stroke episodes (MELAS), myoclonic encephalopathy with ragged-red fibers (MERRF), and encephalopathies. Each phenotype may begin by different ways. The electromiography showed myopathy in 39 cases and various types of neuropathy in 10. Ragged-red COX negative fibers or widespread electron microscopic abnormalities were found in 47 cases. Simple deletions, multiple deletions and three different point mutations were observed. Deficiency of complexes I, II, III and IV were found alone or in different associations. Conclusions. MRCD shows wide variations in clinical, genetic and biochemical studies. Some patients with nonspecific manifestations, mainly of central nervous system, need careful attention and to be on account of diagnostic suspicion (AU)

[Mitochondrial encephalomyopathies and West's syndrome: a frequently underdiagnosed association]. / Encefalomiopatías mitocondriales y síndrome de West: una asociación frecuentemente infradiagnosticada.

INTRODUCTION: West's syndrome is known to have symptomatic, cryptogenetic and idiopathic forms. Greater knowledge of the different pathologies and the development of new diagnostic techniques have allowed the list of symptomatic forms to be extended and congenital disorders of the metabolism account for a significant percentage as an aetiopathogenic factor. Yet, although it is known that mitochondrial cytopathies can trigger the development of West's syndrome, few reports exist concerning their association. AIMS: Our aim in this paper is to report on four cases of West's syndrome in which a mitochondrial cytopathy was shown to be an aetiopathogenic factor. CASE REPORTS: Two females and two males aged between 2 and 10 months, who were suffering from West's syndrome. Biochemical and neuroimaging findings suggested a possible mitochondrial cytopathy, which was later confirmed in the four cases on observing a partial deficiency of some of the complexes of the mitochondrial respiratory chain in muscles; this was found to be simple in the first three (complexes III, I and IV, respectively) and combined in the fourth (complexes I and IV). CONCLUSIONS: Infantile spasms should be considered as one of the ways mitochondrial encephalomyopathies manifest themselves. As part of the process of diagnosing West's syndrome, we recommend tests be carried out to determine the levels of lactic and pyruvic acid, carnitine and amino acids in plasma, and possibly in the cerebrospinal fluid, as well as those of amino acids and organic acids in urine. A muscular biopsy must also be carried out in patients who are strongly suspected of having a mitochondrial cytopathy, as well as the corresponding molecular genetic study.