Myasthenia, myositis, mitochondrial myopathy: Research highlights 2026 – No. 3
Discover in this new research highlight information on predictive factors for the progression of a form of myositis, the role of complement in myasthenia, and recent work on a form of mitochondrial myopathy.
Predicting rapid progression in antisynthetase syndrome
In France, nearly 1,500 people are followed in expert centres for antisynthetase syndrome, a form of inflammatory myopathy associated with lung involvement. While this lung involvement may progress slowly, it can sometimes worsen much more rapidly (within days or weeks), making the identification of predictive factors for rapid progression crucial. This was the aim of the TYPASS study, which analysed the medical records of 132 adults followed in seven expert centres in north-eastern France for antisynthetase syndrome with lung involvement. Rapid progression occurred in nearly 40% of patients, and three factors could help distinguish these patients from the others: they more frequently had fever, “organising pneumonia”-type lung involvement and pleural effusion, meaning fluid accumulation in the membranes surrounding the lungs. The presence of these three features at diagnosis could in the future lead to closer monitoring or even more intensive treatment.
A 3D model confirms the key role of complement in anti-AChR myasthenia
The serum of a person with autoimmune myasthenia carrying “anti-AChR” autoantibodies contains autoantibodies directed against acetylcholine receptors. When applied to a new 3D model of a functional human neuromuscular junction, this serum caused a significant increase in membrane attack complex (MAC) deposits at the surface of the neuromuscular junction and reduced transmission from nerve to muscle: neurotransmission dropped by 70 to 80% within 24 hours and remained impaired on day 7. MAC is composed of complement fractions C5 and C9. Administration of zilucoplan, a drug specifically targeting C5, prevented MAC deposits and preserved neuromuscular junction function.
Better understanding of a mitochondrial myopathy
A team of Italian researchers identified a new mutation in a young patient with a form of mitochondrial myopathy called MEOAL (Mitochondrial Episodic myopathy with or without Optic Atrophy and reversible Leukoencephalopathy). This rare disease manifests from childhood with muscle weakness and exercise intolerance. It is caused by a mutation in the FDX2 gene encoding a protein essential for mitochondrial function, the “energy powerhouses” of our cells. The mutation carried by this patient leads to reduced levels of this protein, disrupting energy production and causing iron accumulation in cells. This study provides a better understanding of the disease and opens the way for future research aimed at correcting these cellular abnormalities.