Mitochondrial myopathies
RSS feedTK2 deficiency: from the treatment of early-stage forms to the first benefits in late-stage forms
On 31 March 2026, the European Commission granted a marketing authorisation (MA) under exceptional circumstances for Kygevvi (doxecitine and doxribtimine) for the treatment of mitochondrial myopathies with thymidine kinase 2 (TK2) deficiency, following the favourable opinion issued by the CHMP (EMA) in January 2026. On 21 May 2026, the HAS granted early access authorisation following … [Read more]
An international consensus on the diagnosis and management of MELAS myopathy
A group of international experts has drawn up recommendations to standardise the diagnosis and management of MELAS myopathy and associated stroke-like episodes (SLEs). Consensus was reached on several statements (using the Delphi method), notably: this myopathy is defined by the occurrence of at least one SLE, associated with mitochondrial dysfunction caused by a mutation in … [Read more]
Two useful biomarkers for a muscle-manifesting mitochondrial disease
Italian and Norwegian researchers report on their work concerning MELAS syndrome (an acronym for Myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes), a mitochondrial cytopathy with neuromuscular manifestations: although the presence of the m.3243A>G variant indicates the existence of the syndrome, the clinical phenotype can vary, ranging from the classic form to less severe phenotypes; neurofilament … [Read more]
TK2 deficiency: from the treatment of early-onset forms to understanding the natural history of late-onset forms
In January 2026, the European Medicines Agency (EMA) issued a favourable opinion on granting marketing authorisation (MA) for Kygevvi (doxecitine and doxribtimine) for the treatment of mitochondrial myopathies with thymidine kinase 2 (TK2) deficiency. This opinion only applies to patients whose symptoms began before the age of 12, as data remains limited when the disease … [Read more]
A new FDX2 mutation identified in a form of mitochondrial myopathy
An Italian team studied the case of a 9-year-old patient with a mitochondrial myopathy called MEOAL (Mitochondrial Episodic Myopathy with or without Optic Atrophy and Reversible Leukoencephalopathy), associated with a new homozygous mutation of FDX2 (c.200+4 A>G). The cellular abnormalities observed are probably related to a decrease in the amount of ferredoxin 2 rather than … [Read more]
A mitochondrial gene responsible for exercise intolerance and rhabdomyolysis
Myologists from the Institut de Myologie (clinicians from the Service of Neuro-Myology and researchers from the CRM and the Morphology Unit) and the Cochin Hospital in the Paris region report the clinical, histological and molecular data of a patient in whom a variant was identified in the XPNPEP3 gene: this mitochondrial gene of nuclear origin … [Read more]
Pyrimidine nucleotide therapy appears to reduce mortality and restore motor function in TK2 deficiency.
A multicentre retrospective study evaluated the effects of daily oral administration (treatment lasting on average approximately two years) of deoxycytidine or deoxythymidine (≤ 800 mg/kg/day) in 38 children and adults with thymidine kinase 2 deficiency (TK2d), an ultra-rare mitochondrial myopathy. The investigators compared their clinical progression with data from a control group of 69 patients … [Read more]
Launch of the MitoGether website, a reference for genetic mitochondrial diseases
To celebrate the World Mitochondrial Disease Week (September 15th to 21st), the MitoGether consortium, comprising 12 patient associations and their families including AFM-Téléthon, is launching a reference website. It aims to be the leading resource on mitochondrial genetic diseases, providing expert information on research, diagnosis, medical care and treatment for these diseases, which are associated … [Read more]
Tadalafil and sildenafil have beneficial effects in patients with primary mitochondrial diseases
Following the identification of a patient with Kearns-Sayre syndrome who reported significant clinical improvements while taking tadalafil, a Hungarian-American research team studied the efficacy of this molecule and sildenafil, either of which was administered to six patients with primary mitochondrial diseases (MELAS, Kearns-Sayre syndrome, etc.) off-label. Analysis of patient fibroblasts incubated with tadalafil or sildenafil … [Read more]
A candidate biomarker for mitochondrial diseases: serum chitotriosidase 1
Elevation of serum chitotriosidase is a biomarker of lysosomal diseases, particularly in Niemann-Pick disease. Recently, the lysosomal component of mitochondrial diseases has been discussed. Serum chitotriosidase (CHIT1) was measured in 117 people with neuromuscular diseases (90 hereditary, 27 inflammatory), 34 with mitochondrial diseases, 8 with Niemann-Pick type C and 38 controls. It is significantly elevated … [Read more]
