In an article published in July 2023, an Italian researcher traces the origins and evolution of myology. This medical science of muscle and its diseases has developed over time, not only due to the advent of tools and technologies that improve our knowledge of muscle, but also due to the international collaborations that punctuate its history.
It was Galen, in Rome in the 2nd century BC, who was the first to give an extremely precise anatomical description of the muscles of the human body. His work was to set the standard for anatomical and medical teaching in the West for over 1,300 years.
The classical era
In 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 19th century saw the clinical characterization of several muscular dystrophies, such as Duchenne muscular dystrophy, by the Italian Gaetano Conte and the French physician Guillaume Duchenne de Boulogne. The latter, by having the first muscle biopsy instrument manufactured, confirmed the tissue aspects described a little earlier by British scientist Edward Meryon. Then French physicians Louis Landouzy and Jules Déjerine described facioscapulohumeral muscular dystrophy, emphasizing its familial nature.
In the early 20th century, Wilhelm Erb coined 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, advances in investigative techniques led to discoveries that enabled better characterization of muscle diseases.
The first was the blood measurement of creatine kinase. Its level rises (sometimes significantly) when muscle cells are damaged, releasing into the bloodstream this enzyme normally contained within the muscle cells.
The advent of the electron microscope, enabling detailed analysis of the components of muscle cells, 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 know-how 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 USA, UK, Canada and France.
New biochemical techniques will improve the identification and diagnosis of neuromuscular diseases in the Netherlands, Sweden and France, enabling the identification of enzyme deficiencies involved in metabolic myopathies such as Pompe disease, McArdle disease or carnitine deficiency.
The molecular era
This was marked by the development of molecular biology techniques and their application to neuromuscular diseases, leading to the identification of the genetic anomalies involved.
Thanks in particular to the Généthon laboratory, which provided the scientific community with the first genome maps, 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 In 1954, 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 the classification of these diseases according to their mode of transmission (autosomal dominant or recessive), accompanied by a specific letter as the genes involved were discovered. Twenty years later, the alphabet no longer suffices, and a new ENMC workshop redefines limb-girdle myopathies and produces a new classification incorporating molecular anomalies in over 28 forms. |
The identification of genetic abnormalities has led to the development of innovative drugs ranging from enzyme replacement therapy in Pompe disease to gene therapy in SMN1 gene-related spinal muscular atrophy, as well as exon skipping and stop codon transection in Duchenne muscular dystrophy.
The era of innovative therapies continues, still relying on collaboration and the exchange of ideas between researchers and doctors from all over the world, notably through congresses such as Myology, organized by the AFM-Téléthon, or the establishment of international collaboration networks such as that of the European neuromuscular reference centers (Euro-NMD).
