Prevalencia de miastenia gravis en la comarca de Osona (Barcelona, Cataluña) / Prevalence of myasthenia gravis in the Catalan county of Osona

INTRODUCCIÓN: La prevalencia descrita de miastenia gravis (MG) oscila entre 5 y 24 casos por 100.000, representando los mayores de 65 años menos del 50% del total. Se presenta la prevalencia de MG en la comarca de Osona (Barcelona, España). Se describen la prevalencia y las características clínicas por grupos de edad, diferenciando los menores y mayores de 65 años. MÉTODOS: El Servicio de Neurología del Hospital General de Vic puso en marcha en el año 1991 un registro comarcal sobre los casos de MG diagnosticados. RESULTADOS: La prevalencia de MG fue de 32,89 × 105 habitantes (IC 95%, 23,86-41,91). La prevalencia estandarizada (población europea) fue del 35,47×105 habitantes (IC 95%, 26,10-44,84). La razón por sexo, mujeres/hombres, es de 1,3. De forma global, el grupo de más de 65 años representa el 62,75% de los casos. Las prevalencias de MG por grandes grupos de edad presentan un carácter marcadamente ascendente, pasando de ningún caso en el grupo de menos de 25 años, a 21,87 × 105 en el grupo de 25 a 64 años, alcanzando 122,35×105 en el grupo de 65 y más años. Las clínicas pretratamiento y a fecha de corte no presentan diferencias estadísticamente significativas (p > 0,05) entre menores y mayores de 65 años. CONCLUSIONES: Se describe la prevalencia más alta comunicada hasta la actualidad. Esta alta prevalencia es a expensas del grupo de más de 65 años. Estos resultados son una nueva alerta para evitar el infradiagnóstico de la MG en el anciano

INTRODUCTION: The reported prevalence of myasthenia gravis ranges between 5 and 24 cases per 100,000, and people over 65 years account for less than 50% of all cases. The prevalence and clinical characteristics of myasthenia gravis in the county of Osona were studied in patients younger and older than 65. METHODS: The study draws from the county-based prospective myasthenia gravis register implemented by the Neurology Department at Hospital General de Vic in 1991. RESULTS: The prevalence of myasthenia gravis was 32.89 × 105 inhabitants (95% CI, 23.86-41.91). The standardized prevalence (European population) was 35.47 × 105 inhabitants (95% CI, 26.10-44.84). The ratio of women to men was 1.3. Overall, the group of patients older than 65 accounted for 62.75% of all cases. The prevalence of myasthenia gravis increased considerably in older age groups. No cases were registered among patients under 25 years old, prevalence was 21.87 × 105 in the 25 to 64 age group, and prevalence in patients over 65 years increased to 122.35×105. The clinical characteristics prior to treatment and at the cut-off date are similar (P > .05) in patients younger than 65 and those aged 65 and older. CONCLUSIONS: These figures show the highest prevalence rate reported to date. This high prevalence is due to the rate observed among patients older than 65. These results provide a new warning that myasthenia gravis may be underdiagnosed in the elderly populatio

Prevalence of myasthenia gravis in the Catalan county of Osona. / Prevalencia de miastenia gravis en la comarca de Osona (Barcelona, Cataluña).

INTRODUCTION: The reported prevalence of myasthenia gravis ranges between 5 and 24 cases per 100,000, and people over 65years account for less than 50% of all cases. The prevalence and clinical characteristics of myasthenia gravis in the county of Osona were studied in patients younger and older than 65. METHODS: The study draws from the county-based prospective myasthenia gravis register implemented by the Neurology Department at Hospital General de Vic in 1991. RESULTS: The prevalence of myasthenia gravis was 32.89×105 inhabitants (95%CI, 23.86-41.91). The standardized prevalence (European population) was 35.47×105 inhabitants (95%CI, 26.10-44.84). The ratio of women to men was 1.3. Overall, the group of patients older than 65 accounted for 62.75% of all cases. The prevalence of myasthenia gravis increased considerably in older age groups. No cases were registered among patients under 25years old, prevalence was 21.87×105 in the 25 to 64 age group, and prevalence in patients over 65 years increased to 122.35×105. The clinical characteristics prior to treatment and at the cut-off date are similar (P>.05) in patients younger than 65 and those aged 65 and older. CONCLUSIONS: These figures show the highest prevalence rate reported to date. This high prevalence is due to the rate observed among patients older than 65. These results provide a new warning that myasthenia gravis may be underdiagnosed in the elderly population.

The expanding field of IgG4-mediated neurological autoimmune disorders.

At least 13 different disease entities affecting the central nervous system, peripheral nervous system and connective tissue of the skin or kidneys are associated with immunoglobulin G4 (IgG4) immune reactivity. IgG4 has always been considered a benign, non-inflammatory subclass of IgG, in contrast to the well-known complement-activating pro-inflammatory IgG1 subclass. A comprehensive review of these IgG4 autoimmune disorders reveals striking similarities in epitope binding and human leukocyte antigen (HLA) associations. Mechanical interference of extracellular ligand-receptor interactions by the associated IgG4 antibodies seems to be the common/converging disease mechanism in these disorders.

Targeted screening for the detection of Pompe disease in patients with unclassified limb-girdle muscular dystrophy or asymptomatic hyperCKemia using dried blood: A Spanish cohort.

We aimed to screen for Pompe disease in patients with unclassified limb-girdle muscular dystrophy (LGMD) or asymptomatic hyperCKemia using dried blood spot (DBS) assays. Subsequently, we aimed to calculate the diagnostic delay between initial symptom presentation and the diagnosis. A prospective, multicenter, observational study was conducted in 348 patients: 146 with unclassified LGMD and 202 with asymptomatic or paucisymptomatic hyperCKemia. We quantified levels of acid alpha-glucosidase (GAA) from dried blood spots analyzed fluorometrically. The test was positive in 20 patients, and Pompe disease was confirmed by genetic testing in 16. Undiagnosed Pompe disease was detected in 7.5% of patients with LGMD and in 2.5% of patients with persistent, idiopathic elevation of serum creatine kinase. The c.-32-13 T > G mutation was found most commonly. The diagnostic delay was 15 years on average. In conclusion, DBS tests are useful and reliable screening tools for Pompe disease. We recommend the dried blood spot test to be included in the diagnostic work-up of patients with unclassified myopathies with proximal weakness and/or hyperCKemia of unknown cause and, when positive, to define the diagnosis, it will have to be confirmed by biochemical and/or molecular genetic analysis.

Myasthenia gravis: descriptive analysis of life-threatening events in a recent nationwide registry.

BACKGROUND AND PURPOSE: Myasthenia gravis (MG) may become life-threatening if patients have respiratory insufficiency or dysphagia. This study aimed to determine the incidence, demographic characteristics, risk factors, response to treatment and outcome of these life-threatening events (LTEs) in a recent, population-based sample of MG patients. METHODS: A retrospective analysis of MG patients who presented with an LTE between 2000 and 2013 was performed. Participants were identified from a neuromuscular diseases registry in Spain that includes 648 patients with MG (NMD-ES). RESULTS: Sixty-two (9.56%) patients had an LTE. Thirty-two were classified as class V according to the MG Foundation of America, and 30 as class IVB. Fifty per cent were previously diagnosed with MG and median duration of the disease before the LTE was 24 months (3-406). The most common related factor was infection (n = 18). All patients received intravenous human immunoglobulin; 11 had a second infusion and six had plasma exchange. Median time to feeding tube removal was 13 days (1-434). Median time to weaning from ventilation was 12 days (3-176), and it was significantly shorter in late onset MG (≥50 years) (P = 0.019). LTEs improved <2 weeks in 55.8% but did not improve until after 1 month in 20% of patients. Four patients died. No other factors influenced mortality or duration of LTEs. CONCLUSIONS: The percentage of LTEs in MG patients was low, particularly amongst those previously diagnosed and treated for the disease. The significant percentage of treatment-resistant LTEs indicates that more effective treatment approaches are needed for this vulnerable sub-population.

Clinical guidelines for late-onset Pompe disease.

Before 2006, Pompe disease or glycogenosis storage disease type II was an incurable disease whose treatment was merely palliative. The development of a recombinant human alpha-glucosidase enzymatic replacement therapy has become the first specific treatment for this illness. The aim of this guide is to serve as reference for the management of the late-onset Pompe disease, the type of Pompe disease that develops after one year of age. In the guide a group of Spanish experts make specific recommendations about diagnosis, follow-up and treatment of this illness. With regard to diagnosis, the dried blood spots method is essential as the first step for the diagnosis of Pompe disease. The confirmation of the diagnosis of Pompe disease must be made by means of an study of enzymatic activity in isolated lymphocytes or a mutation analysis of the alpha-glucosidase gene. With regard to treatment with enzymatic replacement therapy, the experts say that is effective improving or stabilizating the motor function and the respiratory function and it must be introduced when the first symptoms attributable to Pompe disease appear.

Guía diagnóstica en el paciente con enfermedad de Charcot-Marie-Tooth / Guidelines for molecular diagnosis of Charcot-Marie-Tooth disease

Introducción: La enfermedad de Charcot-Marie-Tooth (CMT) es la neuropatía hereditaria más frecuente. Clásicamente dividida según su patrón de herencia y de alteración de la velocidad de conducción motora (VCM) del nervio mediano, CMT incluye cinco grandes categorías: CMT1 (herencia autosómica dominante [AD] o ligada al sexo, y VCM < 38 m/s); CMT2 (herencia AD o ligada al sexo y VCM > 38 m/s); CMT4 (herencia autosómica recesiva [AR] y VCM muy lentificada); AR-CMT2 (forma recesiva con VCM > 38 m/s), y DI-CMT (forma intermedia con herencia AD y VCM entre 30 y 40 m/s). Pese a su estereotipado cuadro clínico (básicamente, semiología polineuropática sensitivo-motora y pie cavo), CMT ha resultado ser uno de los síndromes neurodegenerativos genéticamente más complejos, con 31 genes patogénicos clonados.Desarrollo: El objetivo de esta guía es efectuar una revisión nosológica de la enfermedad de CMT, con énfasis en las directrices para llevar a cabo el diagnóstico molecular. A tal fin, revisamos los estudios de epidemiología y genética, y los genotipos descritos en España. Conclusiones: En la inmensa mayoría de los pacientes con CMT, las mutaciones recaen en un reducido número de genes: para CMT1, PMP22, GJB1 y MPZ; para CMT2, MFN2 y GJB1; para CMT4, GDAP1, y NDRG1, HK1 y SH3TC2 (sujetos de etnia gitana); para AR-CMT2, GDAP1, y para DI-CMT, GJB1 y MPZ. Por su baja prevalencia, las mutaciones en otros genes sólo deberían investigarse cuando las anteriores han sido descartadas. Se desaconseja el uso indiscriminado de paneles de múltiples genes para el diagnóstico molecular de la enfermedad (AU)

Introduction: Charcot-Marie-Tooth disease (CMT) is the most frequent form of inherited neuropathy. In accordance with the inheritance pattern and degree of slowing of motor conduction velocity (MCV) of the median nerve, CMT encompasses five main forms: CMT1 (autosomal dominant [AD] or X-linked transmission and MCV < 38 m/s); CMT2 (AD or X-linked transmission and MCV > 38 m/s); CMT4 (autosomal recessive [AR] and severe slowing of MCV); AR-CMT2 (AR transmission and MCV > 38 m/s); and DI-CMT (intermediate form with AD transmission and MCV between 30 and 40 m/s). In spite of its stereotyped semiological repertoire (basically, symptoms and signs of sensory-motor polyneuropathy and pes cavus), CMT seems to be one of the most complex hereditary neurodegenerative syndromes, 31 causative genes having been cloned.Development: This paper is aimed at performing a nosological review of the disease, emphasising the guidelines for its molecular diagnosis. Genetic epidemiological studies and genotypes reported in Spanish patients are revised.Conclusions: In the great majority of CMT cases, mutations involve a reduced number of genes, namely: for CMT1, PMP22, GJB1 and MPZ; for CMT2, MFN2 and GJB1; for CMT4, GDAP1, and NDRG1, HK1 and SH3TC2 (gypsies); for AR-CMT2, GDAP1; and for DI-CMT, GJB1 and MPZ. Given their low prevalence, mutations in other pathogenic genes should be investigated after discarding the previous ones. There is no place for the indiscriminate use of diagnostic CMT genetic panels (AU)

Long-lasting treatment effect of rituximab in MuSK myasthenia.

OBJECTIVE: Rituximab has emerged as an efficacious option for drug-resistant myasthenia gravis (MG). However, reports published only describe the short-term follow-up of patients treated and little is known about their long-term clinical and immunologic evolution. Our objective was to report the clinical and immunologic long-term follow-up of 17 patients (6 MuSK+MG and 11 AChR+MG) and compare the response between AChR+MG and MuSK+MG patients. METHODS: Myasthenia Gravis Foundation America postintervention status and changes in treatment and antibody titers were periodically determined. Lymphocyte subpopulations, total immunoglobulin, immunoglobulin G (IgG) anti-MuSK subclasses, and anti-tetanus toxoid IgG before and after treatment were also studied. RESULTS: After a mean post-treatment period of 31 months, 10 of the AChR+MG patients improved but 6 of them needed reinfusions. In contrast, all MuSK+MG patients achieved a remission (4/6) or minimal manifestations (2/6) status and no reinfusions were needed. Consequently, in the MuSK+MG group, prednisone doses were significantly reduced and concomitant immunosuppressants could be withdrawn. Clinical improvement was associated with a significant decrease in the antibody titers only in the 6 MuSK+MG patients. At last follow-up MuSK antibodies were negative in 3 of these patients and showed a decrease of over 80% in the other 3. CONCLUSION: In view of the long-lasting benefit observed in MuSK+MG patients, we recommend to use rituximab as an early therapeutic option in this group of patients with MG if they do not respond to prednisone. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that IV rituximab improves the clinical and immunologic status of patients with MuSK+MG.

[Guidelines for molecular diagnosis of Charcot-Marie-Tooth disease]. / Guía diagnóstica en el paciente con enfermedad de Charcot-Marie-Tooth.

INTRODUCTION: Charcot-Marie-Tooth disease (CMT) is the most frequent form of inherited neuropathy. In accordance with the inheritance pattern and degree of slowing of motor conduction velocity (MCV) of the median nerve, CMT encompasses five main forms: CMT1 (autosomal dominant [AD] or X-linked transmission and MCV < 38 m/s); CMT2 (AD or X-linked transmission and MCV > 38 m/s); CMT4 (autosomal recessive [AR] and severe slowing of MCV); AR-CMT2 (AR transmission and MCV > 38 m/s); and DI-CMT (intermediate form with AD transmission and MCV between 30 and 40 m/s). In spite of its stereotyped semiological repertoire (basically, symptoms and signs of sensory-motor polyneuropathy and pes cavus), CMT seems to be one of the most complex hereditary neurodegenerative syndromes, 31 causative genes having been cloned. DEVELOPMENT: This paper is aimed at performing a nosological review of the disease, emphasising the guidelines for its molecular diagnosis. Genetic epidemiological studies and genotypes reported in Spanish patients are revised. CONCLUSIONS: In the great majority of CMT cases, mutations involve a reduced number of genes, namely: for CMT1, PMP22, GJB1 and MPZ; for CMT2, MFN2 and GJB1; for CMT4, GDAP1, and NDRG1, HK1 and SH3TC2 (gypsies); for AR-CMT2, GDAP1; and for DI-CMT, GJB1 and MPZ. Given their low prevalence, mutations in other pathogenic genes should be investigated after discarding the previous ones. There is no place for the indiscriminate use of diagnostic CMT genetic panels.

Identification of novel GH-regulated genes in C2C12 cells.

Growth hormone (GH) is the main regulator of longitudinal growth before puberty, and treatment with human recombinant (rh) GH can increase muscle strength. Nevertheless, molecular mechanisms responsible remain mostly unknown. Many physiological effects of GH require hormone-mediated changes in gene expression. In an attempt to gain insight into the mechanism of GH action in muscle cells we evaluated the effects of rhGH on gene expression profile in a murine skeletal muscle cell line C2C12. The objective of the work was to identify changes in gene expression in the murine skeletal muscle cell line C2C12 after rGH treatment using microarray assays. C2C12 murine skeletal muscle cell cultures were differentiated during 4 days. After 16 h growing in serum-free medium, C2C12 myotubes were stimulated during 6 h with 500 ng/ml rhGH. Four independent sets of experiments were performed to identify GH-regulated genes. Total RNA was isolated and subjected to analysis. To validate changes candidate genes were analyzed by real-time quantitative polymerase chain reaction. One hundred and fifty-four differentially expressed genes were identified; 90 upregulated and 64 downregulated. Many had not been previously identified as GH-responsive. Real-time PCR in biological replicates confirmed the effect of rGH on 15 genes: Cish, Serpina3g, Socs2, Bmp4, Tnfrsf11b, Rgs2, Tgfbr3, Ugdh, Npy1r, Gbp6, Tgfbi, Tgtp, Btc, Clec3b, and Bcl6. This study shows modifications in the gene expression profile of the C2C12 cell line after rhGH exposure. In vitro and gene function analysis revealed genes involved in skeletal and muscle system as well as cardiovascular system development and function.

Allogeneic hematopoietic SCT as treatment option for patients with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE): a consensus conference proposal for a standardized approach.

Allogeneic hematopoietic SCT (HSCT) has been proposed as a treatment for patients with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). HSCT has been performed in nine patients using different protocols with varying success. Based on this preliminary experience, participants of the first consensus conference propose a common approach to allogeneic HSCT in MNGIE. Standardization of the transplant protocol and the clinical and biochemical assessments will allow evaluation of the safety and efficacy of HSCT as well as optimization of therapy for patients with MNGIE.

Redefining dysferlinopathy phenotypes based on clinical findings and muscle imaging studies.

BACKGROUND: The most frequent phenotypes of dysferlin myopathy are limb-girdle muscular dystrophy 2B (LGMD2B) and Miyoshi myopathy (MM). Our objective was to find clinical or MRI markers to differentiate phenotypes of dysferlin myopathy regardless of initial symptoms. METHODS: This retrospective study included 29 patients with confirmed mutations in the DYSF gene (14 MM, 12 LGMD2B, 1 asymptomatic hyperCKemia, and 2 symptomatic carriers). All underwent an annual clinical examination (Medical Research Council scale), functional status assessment, and creatine kinase, pulmonary, and cardiac testing. For research purposes, we performed lower limb MRI studies in all 29 patients to identify the pattern of muscle impairment and to quantify involvement. Statistical correlations between MRI findings and phenotype, disease duration, and functional status were determined. RESULTS: The mean clinical follow-up was 6.4 +/- 5.7 years. No significant differences were found in the rate of progression, functional prognosis, or mutations between patients with MM and patients with LGMD2B. The MRI pattern of muscle involvement was the same for patients with MM and patients with LGMD2B. The adductor magnus and gastrocnemius medialis were the first to be impaired in both phenotypes. The progression of muscle involvement correlated with clinical status. CONCLUSIONS: Splitting dysferlin myopathy into separate phenotypes does not reveal significant differences in terms of rate of progression, prognosis, genotype, or MRI pattern. The finding that proximal and distal muscles are already impaired in the MRI at onset in both MM and LGMD2B favors grouping all phenotypes under the term dysferlin myopathy.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society - first revision.

BACKGROUND: Consensus guidelines on the definition, investigation, and treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have been previously published in European Journal of Neurology and Journal of the Peripheral Nervous System. OBJECTIVES: To revise these guidelines. METHODS: Disease experts, including a representative of patients, considered references retrieved from MEDLINE and Cochrane Systematic Reviews published between August 2004 and July 2009 and prepared statements that were agreed in an iterative fashion. RECOMMENDATIONS: The Task Force agreed on Good Practice Points to define clinical and electrophysiological diagnostic criteria for CIDP with or without concomitant diseases and investigations to be considered. The principal treatment recommendations were: (i) intravenous immunoglobulin (IVIg) (Recommendation Level A) or corticosteroids (Recommendation Level C) should be considered in sensory and motor CIDP; (ii) IVIg should be considered as the initial treatment in pure motor CIDP (Good Practice Point); (iii) if IVIg and corticosteroids are ineffective, plasma exchange (PE) should be considered (Recommendation Level A); (iv) if the response is inadequate or the maintenance doses of the initial treatment are high, combination treatments or adding an immunosuppressant or immunomodulatory drug should be considered (Good Practice Point); (v) symptomatic treatment and multidisciplinary management should be considered (Good Practice Point).

Guidelines for treatment of autoimmune neuromuscular transmission disorders.

BACKGROUND: Important progress has been made in our understanding of the autoimmune neuromuscular transmission (NMT) disorders; myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS) and neuromyotonia (Isaacs' syndrome). METHODS: To prepare consensus guidelines for the treatment of the autoimmune NMT disorders, references retrieved from MEDLINE, EMBASE and the Cochrane Library were considered and statements prepared and agreed on by disease experts. CONCLUSIONS: Anticholinesterase drugs should be given first in the management of MG, but with some caution in patients with MuSK antibodies (good practice point). Plasma exchange is recommended in severe cases to induce remission and in preparation for surgery (recommendation level B). IvIg and plasma exchange are effective for the treatment of MG exacerbations (recommendation level A). For patients with non-thymomatous MG, thymectomy is recommended as an option to increase the probability of remission or improvement (recommendation level B). Once thymoma is diagnosed, thymectomy is indicated irrespective of MG severity (recommendation level A). Oral corticosteroids are first choice drugs when immunosuppressive drugs are necessary (good practice point). When long-term immunosuppression is necessary, azathioprine is recommended to allow tapering the steroids to the lowest possible dose whilst maintaining azathioprine (recommendation level A). 3,4-Diaminopyridine is recommended as symptomatic treatment and IvIG has a positive short-term effect in LEMS (good practice point). Neuromyotonia patients should be treated with an antiepileptic drug that reduces peripheral nerve hyperexcitability (good practice point). For paraneoplastic LEMS and neuromyotonia optimal treatment of the underlying tumour is essential (good practice point). Immunosuppressive treatment of LEMS and neuromyotonia should be similar to MG (good practice point).

Partial dysferlin reconstitution by adult murine mesoangioblasts is sufficient for full functional recovery in a murine model of dysferlinopathy.

Dysferlin deficiency leads to a peculiar form of muscular dystrophy due to a defect in sarcolemma repair and currently lacks a therapy. We developed a cell therapy protocol with wild-type adult murine mesoangioblasts. These cells differentiate with high efficiency into skeletal muscle in vitro but differ from satellite cells because they do not express Pax7. After intramuscular or intra-arterial administration to SCID/BlAJ mice, a novel model of dysferlinopathy, wild-type mesoangioblasts efficiently colonized dystrophic muscles and partially restored dysferlin expression. Nevertheless, functional assays performed on isolated single fibers from transplanted muscles showed a normal repairing ability of the membrane after laser-induced lesions; this result, which reflects gene correction of an enzymatic rather than a structural deficit, suggests that this myopathy may be easier to treat with cell or gene therapy than other forms of muscular dystrophies.

A new phenotype of dysferlinopathy with congenital onset.

We report two patients with a new phenotype of dysferlinopathy presenting as congenital muscular disease. Both patients showed weakness in proximal lower limbs and neck flexor muscles at birth. The presence of normal CK levels during the first years should be noted. Initial MRI showed no abnormalities but short-time-inversion-recovery (STIR) sequences revealed a striking myoedema in gastrocnemius and hamstring muscles at the age of 5. Muscle biopsy showed mild dystrophic features and the absence of dysferlin. Dysferlin gene (DYSF) analysis revealed a p.Ala927LeufsX21 mutation in a homozygous state in both siblings. This new phenotype widens the clinical spectrum of dysferlin myopathies.

Characterization of novel CAPN3 isoforms in white blood cells: an alternative approach for limb-girdle muscular dystrophy 2A diagnosis.

Limb-girdle muscular dystrophy type 2A (LGMD2A) is an autosomal recessive disorder caused by mutations in the CAPN3 gene. Its definitive diagnosis is laborious, since the clinical phenotype is often similar to other types of muscular dystrophy and since the CAPN3 gene encompasses a large genomic region with more than 300 pathogenic mutations described to date. In fact, it is estimated that nearly 25% of the cases with a phenotype suggestive of LGMD2A do not have mutations in the CAPN3 gene and that, in up to 22% of the cases, only one mutation is identified. In the present work, we have characterised CAPN3 messenger RNA (mRNA) expression in peripheral blood, and we have performed a retrospective diagnostic study with 26 LGMD2A patients, sequencing a transcript of CAPN3 present in white blood cells (WBCs). The 25% of the mutations presented in this paper (7/28) act modifying pre-mRNA splicing of the CAPN3 transcript, including the first deep-intronic mutation described to date in the CAPN3 gene. Our results determine that the sequencing of CAPN3 transcripts present in WBCs could be applied as a new approach for LGMD2A diagnosis. This method improves and simplifies diagnosis, since it combines the advantages of mRNA analysis in a more accessible and rapidly regenerated tissue. However, the lack of exon 15 in the CAPN3 isoforms present in blood, and the presence of mRNA degradation make it necessary to combine mRNA and DNA analyses in some specific cases.