Dihydropyridine receptor (DHPR, CACNA1S) congenital myopathy.
Fiche publication
Date publication
avril 2017
Journal
Acta neuropathologica
Auteurs
Membres identifiés du Cancéropôle Est :
Dr THOMPSON Julie
Tous les auteurs :
Schartner V, Romero NB, Donkervoort S, Treves S, Munot P, Pierson TM, Dabaj I, Malfatti E, Zaharieva IT, Zorzato F, Abath Neto O, Brochier G, Lornage X, Eymard B, Taratuto AL, Böhm J, Gonorazky H, Ramos-Platt L, Feng L, Phadke R, Bharucha-Goebel DX, Sumner CJ, Bui MT, Lacene E, Beuvin M, Labasse C, Dondaine N, Schneider R, Thompson J, Boland A, Deleuze JF, Matthews E, Pakleza AN, Sewry CA, Biancalana V, Quijano-Roy S, Muntoni F, Fardeau M, Bönnemann CG, Laporte J
Lien Pubmed
Résumé
Muscle contraction upon nerve stimulation relies on excitation-contraction coupling (ECC) to promote the rapid and generalized release of calcium within myofibers. In skeletal muscle, ECC is performed by the direct coupling of a voltage-gated L-type Ca(2+) channel (dihydropyridine receptor; DHPR) located on the T-tubule with a Ca(2+) release channel (ryanodine receptor; RYR1) on the sarcoplasmic reticulum (SR) component of the triad. Here, we characterize a novel class of congenital myopathy at the morphological, molecular, and functional levels. We describe a cohort of 11 patients from 7 families presenting with perinatal hypotonia, severe axial and generalized weakness. Ophthalmoplegia is present in four patients. The analysis of muscle biopsies demonstrated a characteristic intermyofibrillar network due to SR dilatation, internal nuclei, and areas of myofibrillar disorganization in some samples. Exome sequencing revealed ten recessive or dominant mutations in CACNA1S (Cav1.1), the pore-forming subunit of DHPR in skeletal muscle. Both recessive and dominant mutations correlated with a consistent phenotype, a decrease in protein level, and with a major impairment of Ca(2+) release induced by depolarization in cultured myotubes. While dominant CACNA1S mutations were previously linked to malignant hyperthermia susceptibility or hypokalemic periodic paralysis, our findings strengthen the importance of DHPR for perinatal muscle function in human. These data also highlight CACNA1S and ECC as therapeutic targets for the development of treatments that may be facilitated by the previous knowledge accumulated on DHPR.
Mots clés
Centronuclear myopathy, Congenital myopathy, Core myopathy, DHPR, Excitation–contraction coupling, Myotubular myopathy, Triad
Référence
Acta Neuropathol.. 2017 Apr;133(4):517-533