An international collaboration that included researchers from the Institute of Myology has discovered a new form of distal myopathy, in 10 men:
- with adult onset (over 30 years of age to 40 years), the muscle condition is distal and progresses slowly (ability to walk is maintained). There is no heart involvement;
- it is caused by abnormalities in the SMPX gene, on the X chromosome;
- thanks to muscle MRI and histopathology, it was possible to describe the characteristics common to these patients, such as sarcoplasmic inclusions.
This condition was identified in 5 different countries, and researchers are suggesting that cases exist in all populations, with a probable founder effect in France and in southern Europe. The abnormalities in the SMPX gene still need to be researched, especially among the small number of male cases, for which biopsy suggests a myofibrillar myopathy.