X-linked myotubular myopathy (MTM) is an extremely rare neuromuscular disease belonging to the very heterogeneous group of congenital myopathies. Revealed at birth, even in utero, it is extremely severe with premature mortality. It results in a major hypotonia with respiratory attack, the whole quickly putting into play the vital prognosis.
The causal gene MTM1 codes for myotubularin, a phosphatase active in several signaling pathways involved in young muscle cells maturation process. Prolonged survival cases have been reported in the literature, and few children with MTM develop an extremely rare and potentially life-threatening complication known as hepatic peliosis during evolution. A first gene therapy trial with encouraging preliminary results is underway in children with myotubular myopathy using a gene therapy drug designed in Genethon.
In an article published in May 2020, Japanese clinicians report two new cases of unrelated children aged 19 months and 9 years, respectively. Both children had acute hemorrhagic syndrome and severe liver failure. A liver transplant from their father saved them. Hepatic peliosis is therefore to be considered as a fairly specific complication of this type of myopathy even if its pathophysiology remains poorly understood. In the context of prolonged survival in children with MTM, whether or not treated with gene therapy, this complication must be detected at regular intervals by liver imaging.
