1. Genotypic and phenotypic features of McArdle disease: insights from the Spanish national registry
- Author
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Joaquín Arenas, Margarita Pérez, Inés García-Consuegra, Irene Vieitez, Carmen Navarro, Alfredo Santalla, Ana María Cabello, Gisela Nogales-Gadea, Juan C. Rubio, Susana Teijeira, Alejandro Lucia, Jonatan R. Ruiz, Miguel A. Martín, and Antoni L. Andreu
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Genotype ,Cross-sectional study ,Disease ,Exercise intolerance ,Genética humana ,Young Adult ,Internal medicine ,Activities of Daily Living ,medicine ,Humans ,Registries ,Family history ,Child ,Alleles ,Aged ,Aged, 80 and over ,Muscle Weakness ,business.industry ,Myoglobinuria ,Cardiorespiratory fitness ,Middle Aged ,medicine.disease ,Psychiatry and Mental health ,Cross-Sectional Studies ,Phenotype ,Spain ,Myophosphorylase ,Disease Progression ,Physical therapy ,Glycogen Phosphorylase, Muscle Form ,Glycogen Storage Disease Type V ,Female ,Surgery ,Neurology (clinical) ,medicine.symptom ,business ,Glycogen storage disease type V - Abstract
Background Published genotype/phenotype data on McArdle disease are limited in sample size. A single national (Spanish) registry of patients with McArdle disease was created with the purpose of analysing their genotypic and phenotypic characteristics. Methods A cross sectional study was conducted, collecting demographic, family history, clinical, genotype and functional capacity data from all patients diagnosed with McArdle disease in the Spanish National Health System up to December 2010. Results 239 cases were recorded (all of Caucasian descent, 102 women; mean±SD age 44±18 years (range 9, 93)); prevalence of ∼1/167 000 people. Two mutant PYGM alleles were identified in 99.6% of cases. Although there was heterogeneity in the severity of symptoms, there were four common diagnostic features: (1) 99.5% of patients reported a history of acute crises of exercise intolerance (accompanied by recurrent myoglobinuria in 50% of cases); (2) in 58% of patients, symptoms started in the first decade of life; (3) 86% of patients repeatedly experienced the ‘second wind’ phenomenon over life; and (4) 99% of patients had a high basal serum level of total creatine kinase (>200 U/l). Clinical presentation of the disease was similar in men and women and worsened with age. Patients who were physically active had higher levels of cardiorespiratory fitness (by 23%, p=0.003) and were more likely to improve their clinical course over a 4 year period compared with inactive patients (OR 225; 95% CI 20.3 to 2496.7). Conclusions The main clinical features of McArdle disease are generally homogeneous and frequently appear during childhood; clinical condition deteriorates with ageing. Active patients have a better clinical outcome and functional capacity.
- Published
- 2012