Lookup NU author(s): Dr Lizzie Harris,
Dr Rita Barresi,
Dr Chiara Marini Bettolo,
Dr Ana Topf,
Professor Volker Straub,
Professor Hanns Lochmuller
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Oxford University Press, 2017.
For re-use rights please refer to the publisher's terms and conditions.
Congenital myopathies define a heterogeneous group of neuromuscular diseases with neonatal or childhood hypotonia and muscle weakness. The genetic cause is still unknown in many patients, precluding genetic counselling and better understanding of the physiopathology. To identify novel genetic causes of congenital myopathies, exome sequencing was performed in three consanguineous families. We identified two homozygous frameshift mutations and a homozygous nonsense mutation in the mitogen-activated protein triple kinase ZAK. In total, six affected patients carry these mutations. Reverse transcription polymerase chain reaction and transcriptome analyses suggested nonsense mRNA decay as a main impact of mutations. The patients demonstrated a generalized slowly progressive muscle weakness accompanied by decreased vital capacities. A combination of proximal contractures with distal joint hyperlaxity is a distinct feature in one family. The low endurance and compound muscle action potential amplitude were strongly ameliorated on treatment with anticholinesterase inhibitor in another patient. Common histopathological features encompassed fibre size variation, predominance of type 1 fibre and centralized nuclei. A peculiar subsarcolemmal accumulation of mitochondria pointing towards the centre of the fibre was a novel histological hallmark in one family. These findings will improve the molecular diagnosis of congenital myopathies and implicate the mitogen-activated protein kinase (MAPK) signalling as a novel pathway altered in these rare myopathies.
Author(s): Vasli N, Harris E, Karamchandani J, Bareke E, Majewski J, Romero NB, Stojkovic T, Barresi R, Tasfaout H, Charlton R, Malfatti E, Bohm J, Marini-Bettolo C, Choquet K, Dicaire MJ, Shao YH, Topf A, O'Ferrall E, Eymard B, Straub V, Blanco G, Lochmuller H, Brais B, Laporte J, Tetreault M
Publication type: Article
Publication status: Published
Print publication date: 01/01/2017
Online publication date: 05/11/2016
Acceptance date: 31/08/2016
ISSN (print): 0006-8950
ISSN (electronic): 1460-2156
Publisher: Oxford University Press
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