Myoadenylate deaminase deficiency: clinico-pathological and molecular study of a series of 27 Spanish cases.

Myoadenylate deaminase deficiency (MADD) is the most common metabolic muscle disorder. Here we report the largest study to date of MADD in Spanish patients, including clinical, histological, and molecular data. Most of the patients presented with moderate clinical symptoms of exercise intolerance, including myalgia, fatigability and cramps. In 70% of the patients, serum creatine kinase (CK) was elevated. Muscle biopsy showed mild, nonspecific alterations with absent histochemical reaction for MAD. Eight cases ofMADD were coincidental with other associated diseases, and had more severe tissue alterations upon muscle biopsy. The mutation C34T in the MAD gene was present in a homozygous state in 26 of the 27 patients. One patient was a compound heterozygote for the C34T/G468T mutations. We conclude that MADD should be suspected in patients with exercise intolerance and with idiopathic hyperCKemia. Since symptoms may be subtle, we recommend routine histochemical analysis of MAD in all muscle biopsies, followed by molecular analysis in MAD-negative cases.

Autosomal dominant congenital fibre type disproportion: a clinicopathological and imaging study of a large family.

Congenital fibre type disproportion (CFTD) is considered a non-progressive or slowly progressive muscle disease with relative smallness of type 1 fibres on pathological examination. Although generally benign, CFTD has a variable natural course and severe progression has been observed in some patients. The pathogenesis of the disorder is unknown and many authors consider CFTD a syndrome with multiple aetiologies rather than a separate clinical entity. A positive family history has been reported in about 40% of cases, but the inheritance pattern is not clear. Both autosomal recessive and dominant modes of inheritance have been suggested. The present paper describes a large, multigenerational kindred that has an inherited myopathy fulfilling the histological criteria of CFTD, with autosomal dominant transmission and high penetrance. The clinical picture, remarkably similar in all affected family members, started in early infancy with mild limb muscle weakness. There was slow progression of symptoms into adulthood, with moderate to severe, mainly proximal, muscle weakness without loss of ambulation. Muscle biopsy from two affected individuals demonstrated predominance of small type 1 muscle fibres without other significant findings. Nerve conduction studies were normal and needle electromyography showed a myopathic pattern. MRI examination performed on three patients from successive generations showed involvement of proximal limb and paraspinal muscles. The clinical and pathological homogeneity in the present family, together with the lack of additional histological abnormalities after decades of disease progression in two affected individuals, supports this being a distinct myopathy with fibre type disproportion. Whether the disease in this family can be regarded as a form of the congenital myopathy known as CFTD or rather a unique condition sharing histological features with CFTD needs further investigation. This is, to our knowledge, the largest kindred with muscle fibre type disproportion reported to date. Our data confirm autosomal dominant inheritance, and this is the first MRI document of this disorder.

[Myopathology. New concept. New laboratory]. / Miopatología. Nuevo concepto. Nuevo laboratorio.

The introduction of molecular genetics in medicine, specifically in the field of neuromuscular pathology, has created a drastic change in the diagnostic approach used for neuromuscular disorders. Diagnosis of muscle biopsy is based on important aspects such as morphology and histochemistry, but nowadays immunohistochemistry and Western blot analysis of certain proteins is of utmost importance for a correct diagnosis in a large number of neuromuscular disorders and is crucial to direct the genetic study, which is also necessary. To date, more than 30 muscular dystrophy types have been genetically characterized, and the protein product is known in most of them as well as its structural location in the muscle fiber and its relation with other muscle proteins and the extracellular matrix. With the diagnostic specificity conferred by the absence of expression by a specific protein or a mutation of a specific gene, we have learned that similar clinical phenotype may occur in different diseases, such as Duchenne muscular dystrophy and gamma-sarcoglycanopathy, but also that mutations in the same gene may cause different clinical phenotypes, as occurs in Miyoshi distal myopathy and limb girdle muscular dystrophy 2B, both caused by mutations in the dysferlin gene. Herein we describe the recommendable diagnostic methodology and strategy to be employed in the study of the large group of the <>, especially focused on the autosomal recessive dystrophies, taking the study of dystrophinopathies as an example.

Miopatología. Nuevo concepto. Nuevo laboratorio / Myopathology. New concept. New laboratory

La irrupción de la genética molecular en medicina y específicamente en el campo de la patología neuromuscular ha supuesto un cambio drástico en el abordaje diagnóstico de las enfermedades neuromusculares. El diagnóstico de la biopsia muscular está basado en importantes pilares como la morfología y la histoquímica, pero en la actualidad el estudio por inmunohistoquímica y Western blot de determinadas proteínas musculares es imprescindible para realizar un diagnóstico de exactitud en un amplio grupo de enfermedades y orienta el estudio genético, igualmente necesario.En la actualidad se han individualizado más de 30 tipos de distrofias musculares caracterizadas genéticamente, conociéndose la proteína producto en la mayoría de ellas, su localización estructural en la fibra muscular y su relación con otras proteínas musculares y de la matriz extracelular. Con la especificidad diagnóstica que confiere la ausencia de expresión de una determinada proteína o una mutación en un determinado gen, hemos aprendido que cuadros clínicos similares pueden aparecer en dos enfermedades distintas, como, por ejemplo, la distrofia muscular de Duchenne y la gamma-sarcoglicanopatía, o que mutaciones en un mismo gen pueden dar lugar a fenotipos clínicos muy diferentes como ocurre en la miopatía distal de Miyoshi y la distrofia de cinturas tipo 213, ambas producidas por mutaciones en el gen de la disferlina.Describimos aquí la estrategia diagnóstica recomendable en el amplio grupo de las denominadas "distrofias de cinturas", centrándonos en las de herencia autosómica recesiva y poniendo como ejemplo metodológico el estudio de las distrofinopatías (AU)

Beta-sarcoglycanopathy (LGMD 2E) in a Spanish family.

Out of 10 autosomal recessive limb-girdle muscular dystrophies reported, 4 are caused by mutations in the genes encoding for sarcoglycans (alpha-, beta-, gamma- and delta-SG). Beta-sarcoglycanopathy (limb-girdle muscular dystrophy 2E) is a genetically heterogeneous disorder which usually presents a severe progressive clinical course. A complete immunohistochemical evaluation of the sarcoglycan complex should be carried out to direct the mutation analysis approach. The present report concerns a Spanish family with a genetically confirmed beta-sarcoglycanopathy. The patient, a 16-year-old female, offspring of a consanguineous marriage, developed a severe limb-girdle muscular dystrophy with a Duchenne-like phenotype. Muscle biopsy showed dystrophic changes and complete absence of the four sarcoglycans. Genetic analysis demonstrated homozygosis for the M100K missense mutation in exon 3, encoding for the proximal extracellular domain. The parents and one sister were found to be carriers. Missense mutations affecting this domain result in the instability of the entire sarcoglycan complex and lead to severe phenotypes as seen in non-sense mutations.

[A brain tissue bank in a neuropathology laboratory. Basic methodology]. / Banco de tejidos Neurológicos en el Laboratorio de Neuropatología. Organización básica.

The Meixoeiro Hospital Brain Bank (BB) was established at the end of 2002. A BB is a tissue collection and storage system, established under the best conditions to carry out prospective morphological, biochemical or molecular studies. The BB should ideally be supported by a donor program, although samples may also be obtained from autopsy material from patients with neurodegenerative diseases. Recruitment of control cases from brains without neurological diseases is basic. The main goal of a BB is to provide brain tissue for research. Each case requires accurate clinical data, a definite diagnosis and optimal conditions of tissue preservation. The use of protocols to standardize the handling and processing of tissues, data recruitment and neuropathological diagnosis is fundamental to assure the quality and homogeneity of samples. Close collaboration between neuropathologists, neurologists and other specialists is essential in all the process. Although important advances in the tissue banking field have been achieved, the number of donors in Spain still remains low. Stronger institutional support as well as public awareness through better diffusion of the information is necessary to increase the number of donors and improve BB development.

Banco de Tejidos Neurológicos en el Laboratorio de Neuropatología. Organización básica / A Brain Bank in a Neuropathology Laboratory. Basic methodology

El Banco de Tejidos Neurológicos (BTN) del Hospital Meixoeiro se implantó a finales del año 2002. Un BTN es un sistema prospectivo de almacenamiento y conservación de tejidos en condiciones óptimas que permitan la realización de cualquier estudio morfológico, bioquímico o molecular. Su funcionamiento debe estar basado en un programa de donación, aunque las muestras pueden proceder tanto de donantes como de autopsias clínicas de pacientes con enfermedades neurodegenerativas. Es importante la obtención de cerebros de personas sin enfermedad neurológica para casos control. El objetivo principal de un BTN es el de proporcionar tejido nervioso para la investigación. Los casos deben tener una buena información clínica, un diagnóstico definitivo y unas condiciones de conservación idóneas. Para asegurar la calidad y homogeneidad de las muestras hay que estandarizar, mediante protocolos, los métodos de obtención, extracción y procesamiento del tejido, la recogida de la información y el diagnóstico neuropatológico. La colaboración multidisciplinar entre neuropatólogos, neurólogos y otros especialistas es básica en todo el proceso. Aunque se están realizando grandes avances en el campo de los Bancos Tisulares, el número de donaciones en España es aún muy bajo. Para estimular las donaciones y potenciar el desarrollo de los BTN, hay que conseguir un mayor apoyo institucional y una mayor concienciación de la sociedad mejorando la información (AU)

Neuromuscular disorders in the Gypsy ethnic group. A short review.

The Roma (Gypsies) are a transnational minority with an estimated population of 10 to 14 million, 8 of which reside in Europe, scattered between the Balkans and Western countries. Similar to other genetically isolated founder populations, the Roma harbour a number of unique or rare autosomal recessive disorders, caused by "private" founder mutations. These genetically homogeneous populations are a unique resource for research into disease phenotypes, genotype/phenotype correlations and possible factors modifying clinical severity. Regarding neuromuscular diseases, the following have been identified: limb girdle muscular dystrophy type 2C also called gamma-sarcoglycanopathy, congenital myasthenic syndrome type 1a, spinal muscular atrophy, and three novel hereditary sensorimotor neuropathies, namely -Lom, -Russe and the congenital cataracts facial dysmorphism neuropathy syndrome. In 1996, a novel demyelinating neuropathy in the Roma was described and the gene was mapped in 8q24. Almost simultaneously, a founder mutation in the gamma-sarcoglycan gene in a group of 24 Romani patients from France, Spain and Italy was discovered by a different group of researchers. The cooperation between these two groups and people from several European countries was fruitful, and in 2001 the 91st Workshop of the European Neuromuscular Center was organized to discuss the above-mentioned diseases in the Roma. Full papers on each of the topics were subsequently published in the 20th Anniversary volume of Acta Myologica, in December 2001. Here, we present a short review of neuromuscular disorders in Gypsies and we discuss the perspectives and future for further studying and research.

Molecular heterogeneity of myophosphorylase deficiency (McArdle's disease): a genotype-phenotype correlation study.

We report on 54 Spanish patients with McArdle's disease from 40 unrelated families. Molecular analysis revealed that the most common R49X mutation was present in 70% of patients and 55% of alleles. The G204S mutation was less frequent and found in 14.8% of patients and 9% of mutant alleles. The W797R mutation was observed in 16.5% of patients, accounting for 13.7% of mutant alleles. Moreover, 78% of mutant alleles among Spanish patients can be identified by using polymerase chain reaction-restriction fragment length polymorphism analysis for the R49X, G204S, and W797R mutations, which makes noninvasive diagnosis possible through molecular genetic analysis of blood DNA. Six novel mutations were found. Three were missense mutations, E348K, R601W, and A703V; two nonsense mutations, E124X and Q754X; and one single base pair deletion, 533 delA. No clear genotype-phenotype correlation emerges from our study. Most of the mutations of uncharged and solvent inaccessible residues and the truncations must disrupt the basic structure of the protein. The mutations of charged residues would be expected to interfere with internal hydrogen bonding networks, introducing severe incompatible partnering that is caused by poor packing or electrostatic repulsions.

Lipomatosis simétrica múltiple: Aportaciónde un caso y revisión de la literatura / Multiple symmetrical lipomatosis. report of a case and review of the literature

La lipomatosis simétrica múltiple es una enfermedad que se caracteriza por presentar múltiples y simétricas masas de tejido adiposo no encapsulado, indoloras y localizadas frecuentemente en cuello, hombros y otras partes del tronco. Habitualmente se asocia a alcoholismo y trastornos metabólicos, y puede cursar con afectación mediastínica y neuropatía. Presentamos el caso de un paciente de 63 años de edad, con importante hábito enólico. Se describen las características clínico-morfológicas, los hallazgos histopatológicos de una biopsia de grasa subcutánea y músculo esquelético, además de otras pruebas complementarias y los posibles tratamientos electivos. Se incluye, además, una amplia revisión de la literatura sobre esta patología (AU)

Evaluation of heart involvement in gamma-sarcoglycanopathy (LGMD2C). A study of ten patients.

Thorough non-invasive cardiovascular studies were conducted in a series of ten gamma-sarcoglycanopathy Gypsy patients with the founder C283Y mutation in 13q12. Results were compared with those obtained in an age-matched group of normal boys and girls. The studies included electrocardiographic and echocardiographic evaluations using pulsed wave Doppler tissue imaging to assess regional diastolic function and myocardial velocities at various levels. This study confirms the significant electrocardiographic abnormalities described in previous studies. Furthermore, measurement of myocardial velocity at different levels demonstrated an abnormal relaxation pattern in the tricuspid annulus in four of the oldest patients, which strongly suggests intrinsic myocardial involvement of the right ventricle. To our knowledge, these specific studies have not been previously performed in a clinically and genetically homogeneous group of gamma-sarcoglycanopathy patients and suggest primary myocardial involvement probably due to gamma-sarcoglycan deficiency in cardiac muscle fibres. Our results could be of interest in the follow-up of these patients and the prevention and treatment of late cardiological complications.

A novel missense mutation (W797R) in the myophosphorylase gene in Spanish patients with McArdle disease.

OBJECTIVE: To investigate the degree of genetic heterogeneity of myophosphorylase deficiency (McArdle disease) in Spain through molecular studies of 10 new patients. DESIGN: The coding sequence of the entire myophosphorylase gene was sequenced in DNA extracted from muscle and blood. Restriction fragment length polymorphism analysis of polymerase chain reaction fragments was used to confirm and simplify detection of a novel mutation. SETTING: A collaborative study between 2 university laboratories in Spain and the United States. RESULTS: Five of the 10 patients harbored a novel missense mutation in exon 20, converting a tryptophan to an arginine (W797R). Three patients were homozygous for the "common" R49X mutation, and the remaining 2 patients were compound heterozygotes for R49X and a previously described missense mutation, G204S. CONCLUSIONS: The W797R missense mutation is the third novel mutation to be identified among Spanish patients. Its relative frequency suggests that it should be added to the R49X mutation in the molecular screening of McArdle disease in Spain.

Adult glycogenosis II with paracrystalline mitochondrial inclusions and Hirano bodies in skeletal muscle.

Hirano bodies constitute eosinophilic intracytoplasmic inclusions, typically seen in the central nervous system, where they are related to senility and certain dementias such as Alzheimer's disease or the Parkinson-dementia complex. They have been found in different tissues of experimental animals and, on rare occasions, in extraocular muscles of elderly individuals. However, to our knowledge they have not been described in skeletal muscle in locations other than extraocular muscles or associated with muscle pathology. Glycogenosis II or Pompe's disease, is a metabolic disorder caused by acid maltase deficiency and is characterized by glycogen accumulation in lysosomes in various tissues, including skeletal muscle. There are three clinical forms depending on age at onset, the most frequent being the childhood form. We present the histopathological and ultrastructural findings of a muscle biopsy performed in a case of the adult form of glycogenosis II which showed, in addition to characteristic lysosomal glycogen storage, paracrystalline mitochondrial inclusions and, as an exceptional finding, intracytoplasmic Hirano bodies in some muscle fibres.

Subsarcolemmal expression of utrophin in neuromuscular disorders: an immunohistochemical study of 80 cases.

The immunohistochemical expression of utrophin in 80 muscle biopsies from patients with dystrophinopathies and other neuromuscular disorders is reported. All biopsy specimens were routinely studied by a battery of 12 histoenzymatic techniques, and immunohistochemistry was performed for spectrin, three domains of dystrophin and two domains of utrophin. Abnormal utrophin expression was observed in all dystrophinopathic muscles compared with normal controls or biopsy samples from several other muscular diseases. Inflammatory myopathies presented abnormal overexpression of utrophin and an abnormal dystrophin immunolabeling pattern. This overexpression of utrophin appears to be directly related to the decrease in dystrophin. We conclude that the study of utrophin is important for the histological interpretation and differential diagnosis of dystrophin-related muscular disorders.

Isolated progressive muscle weakness with tubular aggregates.

We report 2 isolated cases of slowly progressive muscle weakness in which tubular aggregates in muscle biopsy were found as the major pathological feature. Tubular aggregates were present in both types of fibers. Electron microscopy revealed the accumulation of double-walled tubular structures in dense subsarcolemmal locations or in smaller amounts within the myofibrils, close to cytoplasmic organelles. Myopathy with tubular aggregates is believed to form a distinct clinico-pathological entity with 3 well-distinguished clinical groups. The cases reported herein would fall into the group of sporadic isolated progressive muscle weakness of which only 3 other cases have been previously described.