The history of myology in Europe
In an article published in July 2023, an Italian researcher traces the birth and development of myology. This medical science of muscle and its diseases has developed over time, not only thanks to the advent of tools and technologies that improve our knowledge of muscle, but also thanks to the international collaborations that have marked its history.
It was Galen, in Rome in the second century BC, who was the first to give an extremely precise anatomical description of the muscles of the human body. His work was a reference in anatomical and medical teaching in the West for more than 1,300 years.
The classical era
During the Renaissance, the anatomical data established by Galen were confirmed by the work of Leonardo da Vinci and Andrea Vesalius. In the 18th century, Luigi Galvani demonstrated the excitability of muscle by an electric current.
The second half of the nineteenth century saw the clinical characterization of several muscular dystrophies, such as Duchenne muscular dystrophy, by the Italian Gaetano Conte and the Frenchman Guillaume Duchenne de Boulogne. The latter, by having the first instrument for taking a muscle biopsy made, confirmed the tissue aspects described a little earlier by the British scientist Edward Meryon. Then the Frenchmen Louis Landouzy and Jules Déjerine described facioscapulohumeral muscular dystrophy, emphasizing its familial nature.
At the beginning of the 20th century, Wilhelm Erb proposed the term "progressive muscular dystrophy" and described the first form of limb-girdle myopathy.
The modern era
In the second half of the twentieth century, developments in investigative techniques led to discoveries that enabled muscle diseases to be better characterized.
The first was the measurement of creatine kinase in the blood. Its level rises (sometimes significantly) when muscle cells are damaged and release this enzyme, normally contained within the muscle cells, into the bloodstream.
The advent of the electron microscope, enabling detailed analysis of muscle cell components, led to the emergence of a whole chapter of structural muscle diseases: congenital myopathies. Similarly, the identification of abnormal mitochondria in muscle biopsies opened up the field of diseases of the mitochondrial respiratory chain: mitochondrial cytopathies.
These discoveries and expertise were shared at international congresses devoted to neuromuscular diseases from 1969 onwards, and through collaborations, internships and the integration of foreign researchers into leading myology laboratories in the United States, the United Kingdom, Canada and France. New biochemical techniques will improve the identification and diagnosis of neuromuscular diseases in the Netherlands, Sweden and France, making it possible to identify the enzyme deficiencies involved in metabolic myopathies such as Pompe's disease, McArdle's disease and carnitine deficiency.
The molecular era
This era was marked by the development of molecular biology techniques and their application to neuromuscular diseases, leading to the identification of the genetic anomalies involved.
It was thanks in particular to the Genethon laboratory, which provided the scientific community with the first genome maps, that these discoveries began to proliferate in the 2000s.
The development of new sequencing techniques has further accelerated the discovery of new genetic anomalies and improved the diagnostic accuracy of hereditary myopathies.
The example of limb-girdle muscular dystrophy
It was in 1954 that Walton and Natrass used the term "limb-girdle muscular dystrophy" to define a new clinical entity, which nevertheless encompassed different forms of myopathy.
An initial workshop organized in 1995 by the European Neuromuscular Center (ENMC) led to a classification of these diseases according to their mode of transmission (autosomal dominant or recessive), accompanied by a specific letter as and when the genes involved were discovered.
Twenty years later, the alphabet was no longer sufficient, and a new ENMC workshop redefined limb-girdle muscular dystrophies and produced a new classification incorporating the molecular abnormalities of more than 28 forms.
The identification of genetic anomalies has led to the development of innovative medicines ranging from enzyme replacement therapy in Pompe disease to gene therapy in spinal muscular atrophy linked to the SMN1 gene, via exon skipping and stop codon transection in Duchenne muscular dystrophy. The era of innovative therapies continues, based as ever on collaboration and the exchange of ideas between researchers and doctors from all over the world, notably through conferences such as Myology, organised by the AFM-Téléthon, or the establishment of international collaboration networks such as the European Neuromuscular Reference Centres (Euro-NMD).”